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ling (Baetz et al., 1995). Stabilization of the pSMAC of CD4+ cytotoxic T lymphocyte (CTL) with a PKC-θ inhibitor quantified increased killing, the first evidence of for an advantage of an intact pSMAC (Beal et al., 2008). Structures similar to pSMACs also form between T cells in homotypic aggregates and are important for intensification of cytokine signals during T cell expansion (Sabatos et al., 2008). The symmetric immunological synapse may serve equally important functions in tolerance induction, priming and differentiation as discussed below. Between chemokine dependent extravasation and MHC-peptide dependent immunological synapse formation T cells rapidly migrate in DC networks of T cell zones (Bajenoff et al., 2006). Rapid migration by T cells can be fully reconstituted with solid phase CCL21, a CCR7 ligand, in vitro (Woolf et al., 2007). This involved polarization and formation of a leading edge that takes the form of a flattened lamellipodium on CCL21 and ICAM-1 coated surfaces (Huang and Dustin, unpublished data). LFA-1 is not required for mobility in T cell zones (Woolf et al., 2007), but LFA-1 increases sensitivity to MHC-peptide complexes up to 100-fold (Bachmann et al., 1997) and ICAM-1 is required for antigen specific arrest in vivo (Scholer et al., 2008). The lamellipodium is a sensory structure and has been shown to be the most sensitive part of a T cell by ~40-fold in elegant studies with laser traps and anti-CD3 coated beads (Negulescu et al., 1996; Wei et al., 1999). Valitutti has also described the probing behavior of lymphocytes undergoing sustained signaling on APCs (Valitutti et al., 1995a). Another important experiment is the demonstration that TCR signaling is continually being renewed by new TCR-MHC-peptide interactions such that blocking the access to new MHC-peptide ligands with MHC antibodies immediately block signaling (Valitutti et al., 1995a). Lamellipodia are coordinated by small G-proteins including Rac-1, which activates the WAVE2 complexes leading to dynamic actin in the perip

ublished data). LFA-1 is not required for mobility in T cell zones (Woolf et al., 2007), but LFA-1 increases sensitivity to MHC-peptide complexes up to 100-fold (Bachmann et al., 1997) and ICAM-1 is required for antigen specific arrest in vivo (Scholer et al., 2008). The lamellipodium is a sensory structure and has been shown to be the most sensitive part of a T cell by ~40-fold in elegant studies with laser traps and anti-CD3 coated beads (Negulescu et al., 1996; Wei et al., 1999). Valitutti has also described the probing behavior of lymphocytes undergoing sustained signaling on APCs (Valitutti et al., 1995a). Another important experiment is the demonstration that TCR signaling is continually being renewed by new TCR-MHC-peptide interactions such that blocking the access to new MHC-peptide ligands with MHC antibodies immediately block signaling (Valitutti et al., 1995a). Lamellipodia are coordinated by small G-proteins including Rac-1, which activates the WAVE2 complexes leading to dynamic actin in the periphery of nascent immunological synapses (Nolz et al., 2006). HS-1, a lymphocyte-specific cortactin is important for forming lamellipodia (Gomez et al., 2006). EVL, a hematopoietic cell member of the ENA-VASP family, is found at the tips of projections touching the APC (Lambrechts et al., 2000). Activation of these systems is not antigen specific and similar structures are induced during non-antigen specific engagement of adhesion molecule like LFA-1 by ICAM-1 (Smith et al., 2003) and CD2 by CD58 (or CD48 in the mouse) (Kaizuka et al., 2009). In response to TCR signals, the SLP-76 signaling module recruits and activates Vav, an exchange factor for Rac and Cdc42. Rac then activates WAVE2 and Cdc42 activates WASP. Both WAVE2 and WASP activate the Arp2/3 complex to generate branched actin networks. WAVE2 is associated with lamellipodial actin (Nolz et al., 2006), whereas WASP is associated with ventral projections such as podosomes and invadipodia (Carman et al., 2007). Behind the lamellipodium is the lamella, whi

hery of nascent immunological synapses (Nolz et al., 2006). HS-1, a lymphocyte-specific cortactin is important for forming lamellipodia (Gomez et al., 2006). EVL, a hematopoietic cell member of the ENA-VASP family, is found at the tips of projections touching the APC (Lambrechts et al., 2000). Activation of these systems is not antigen specific and similar structures are induced during non-antigen specific engagement of adhesion molecule like LFA-1 by ICAM-1 (Smith et al., 2003) and CD2 by CD58 (or CD48 in the mouse) (Kaizuka et al., 2009). In response to TCR signals, the SLP-76 signaling module recruits and activates Vav, an exchange factor for Rac and Cdc42. Rac then activates WAVE2 and Cdc42 activates WASP. Both WAVE2 and WASP activate the Arp2/3 complex to generate branched actin networks. WAVE2 is associated with lamellipodial actin (Nolz et al., 2006), whereas WASP is associated with ventral projections such as podosomes and invadipodia (Carman et al., 2007). Behind the lamellipodium is the lamella, which has also been referred to as a focal zone in migrating T cells (Smith et al., 2005). These zones are rich in adhesion sites and integrin binding adapter talin, which is also a marker of the pSMAC. T cell may arrest migration and form a stable synapse, or alternatively, they may continue to migrate and integrate signals on the move. This rapid migration during antigen recognition contrasts with the stable synapse and has different functional consequences. Rapid migration during antigen recognition is observed in T-DC interactions in vitro early stages of T cell interaction with low dose agonist stimuli in vivo (Henrickson et al., 2008) and with low potency TCR stimuli (Skokos et al., 2007). There are at least two explanations for these mobile junctions or “kinapses”(Dustin, 2008). Certain chemokinetic signals, such as CCL21 signals, can compete with antigen stop signals (Bromley et al., 2000). The ability of T cells to migrate for some period followed by arrest may relate to signaling thresholds or time dep

ch has also been referred to as a focal zone in migrating T cells (Smith et al., 2005). These zones are rich in adhesion sites and integrin binding adapter talin, which is also a marker of the pSMAC. T cell may arrest migration and form a stable synapse, or alternatively, they may continue to migrate and integrate signals on the move. This rapid migration during antigen recognition contrasts with the stable synapse and has different functional consequences. Rapid migration during antigen recognition is observed in T-DC interactions in vitro early stages of T cell interaction with low dose agonist stimuli in vivo (Henrickson et al., 2008) and with low potency TCR stimuli (Skokos et al., 2007). There are at least two explanations for these mobile junctions or “kinapses”(Dustin, 2008). Certain chemokinetic signals, such as CCL21 signals, can compete with antigen stop signals (Bromley et al., 2000). The ability of T cells to migrate for some period followed by arrest may relate to signaling thresholds or time dependent down-regulation of CCR7. This gives the T cells flexibility in looking at different amounts of antigen on DCs-a few DCs with high amounts of MHC-peptide can stop T cells whereas many DCs with few antigen can sustain signaling until the T cells resets its sensitivity and can arrest (Henrickson et al., 2008). Weaker MHC-peptide never overcome the chemokinetic signals and continually migrate in DC networks (Skokos et al., 2007). T cells encountering these weaker ligands cannot arrest in the steady state and only integrate signals through kinapses. This mode of signal integration is sufficient to induce an alternative mode of tolerance induction when the antigen is presented on many DCs through scavenger receptor DEC-205. The failure of some weaker self-antigens to stop T cells may contribute the failure of tolerance induction and the development of autoimmuity (Zehn and Bevan, 2006). In autoimmunity the combination of strong innate signals and weak TCR signals can lead to robust responses, although there

endent down-regulation of CCR7. This gives the T cells flexibility in looking at different amounts of antigen on DCs-a few DCs with high amounts of MHC-peptide can stop T cells whereas many DCs with few antigen can sustain signaling until the T cells resets its sensitivity and can arrest (Henrickson et al., 2008). Weaker MHC-peptide never overcome the chemokinetic signals and continually migrate in DC networks (Skokos et al., 2007). T cells encountering these weaker ligands cannot arrest in the steady state and only integrate signals through kinapses. This mode of signal integration is sufficient to induce an alternative mode of tolerance induction when the antigen is presented on many DCs through scavenger receptor DEC-205. The failure of some weaker self-antigens to stop T cells may contribute the failure of tolerance induction and the development of autoimmuity (Zehn and Bevan, 2006). In autoimmunity the combination of strong innate signals and weak TCR signals can lead to robust responses, although there are differences in the kinetics of T cell release from lymph nodes and fitness of the cells that may limit memory generation autoimmunity (Zehn and Bevan, 2006). Thus, a migrating T cell sensing MHC-peptide complexes at its leading edge can integrate signals and make decisions about tolerance to abundant antigens, but not rare self-antigens. How do T cells form a synapse? T cells stopped by MHC-peptide complexes remained highly dynamics with prominent cycles of extension and retraction around a pivot point (Dustin et al., 1997; Valitutti et al., 1995a). Studies on planar bilayers reveal what appears to be an early spreading, receptor engagement and contractile process that form the cSMAC over a period of 5 minutes and which is F-actin dependent (Grakoui et al., 1999). These results also led to speculation that myosin II based contraction might also be involved because of the substantial decreases in contact size and the speed of receptor cluster movement (Dustin and Cooper, 2000; Grakoui et al., 1999). Simila

are differences in the kinetics of T cell release from lymph nodes and fitness of the cells that may limit memory generation autoimmunity (Zehn and Bevan, 2006). Thus, a migrating T cell sensing MHC-peptide complexes at its leading edge can integrate signals and make decisions about tolerance to abundant antigens, but not rare self-antigens. How do T cells form a synapse? T cells stopped by MHC-peptide complexes remained highly dynamics with prominent cycles of extension and retraction around a pivot point (Dustin et al., 1997; Valitutti et al., 1995a). Studies on planar bilayers reveal what appears to be an early spreading, receptor engagement and contractile process that form the cSMAC over a period of 5 minutes and which is F-actin dependent (Grakoui et al., 1999). These results also led to speculation that myosin II based contraction might also be involved because of the substantial decreases in contact size and the speed of receptor cluster movement (Dustin and Cooper, 2000; Grakoui et al., 1999). Similar results were obtained in live cell-cell systems in which TCR in small clusters moved to the center to form the cSMAC (Krummel et al., 2000). However, these authors eventually rejected the hypothesis that myosin II is required for this contraction and transport process because knockdown of myosin IIA did not appear to eliminate the ability to form a synapse with an APC (Jacobelli et al., 2004). More recent studies in the planar bilayer model actually supported the hypothesis that myosin IIA is important for microcluster transport and signal amplification in that system and for signal amplification in cell-cell models (Ilani et al., 2009). It is possible that there are alternative mechanisms to form a cSMAC in cell-cell systems that involve directed vesicular transport, which would be myosin II independent (Das et al., 2004). Nonetheless, the extension of an APC embracing lamellipodium is observed in cell-cell systems (Antón et al., 2002; Tskvitaria-Fuller et al., 2003). In Jurkat T leukemia cells, spreading

r results were obtained in live cell-cell systems in which TCR in small clusters moved to the center to form the cSMAC (Krummel et al., 2000). However, these authors eventually rejected the hypothesis that myosin II is required for this contraction and transport process because knockdown of myosin IIA did not appear to eliminate the ability to form a synapse with an APC (Jacobelli et al., 2004). More recent studies in the planar bilayer model actually supported the hypothesis that myosin IIA is important for microcluster transport and signal amplification in that system and for signal amplification in cell-cell models (Ilani et al., 2009). It is possible that there are alternative mechanisms to form a cSMAC in cell-cell systems that involve directed vesicular transport, which would be myosin II independent (Das et al., 2004). Nonetheless, the extension of an APC embracing lamellipodium is observed in cell-cell systems (Antón et al., 2002; Tskvitaria-Fuller et al., 2003). In Jurkat T leukemia cells, spreading on anti-CD3 coated surfaces form a well organized F-actin ring at early time points, and that this ring appear to break up after a contractile phase (Bunnell et al., 2001). These studies suggest that the initial contact expansion is mediated by F-actin driven protrusion, which then shift to a more dynamic extension-retraction process during sustained signaling. In fact the pivoting process observed with solid phase MHC-peptide complexes suggest that the stop was based on loss of persistent polarity. What could account for the ability of cells to rapidly transition from migration to arrest? Quantitative analysis of TCR dynamics and cell spreading provided insight into how the stable and dynamic characteristics of the synapse are reconciled. Observations of contact areas on planar bilayers with total internal reflection fluorescence microscopy (TIRFM) reveal that the dSMAC is a radial lamellipodium. First, TCR in cells form synapses over a period of 30 minutes and even after cSMAC formation, sub-micron TCR clus

on anti-CD3 coated surfaces form a well organized F-actin ring at early time points, and that this ring appear to break up after a contractile phase (Bunnell et al., 2001). These studies suggest that the initial contact expansion is mediated by F-actin driven protrusion, which then shift to a more dynamic extension-retraction process during sustained signaling. In fact the pivoting process observed with solid phase MHC-peptide complexes suggest that the stop was based on loss of persistent polarity. What could account for the ability of cells to rapidly transition from migration to arrest? Quantitative analysis of TCR dynamics and cell spreading provided insight into how the stable and dynamic characteristics of the synapse are reconciled. Observations of contact areas on planar bilayers with total internal reflection fluorescence microscopy (TIRFM) reveal that the dSMAC is a radial lamellipodium. First, TCR in cells form synapses over a period of 30 minutes and even after cSMAC formation, sub-micron TCR clusters continue to form in the periphery (Varma et al., 2006). These small TCR microclusters forming later during stimulation are invisible to wide-field imaging on bilayers or cell-cell system. In fact, the continual formation of small microclusters to sustain signaling has only recently been observed in cell-cell systems using a combination of laser tweezers and spinning disk confocal microscopy (Oddos et al., 2008). This sustained movement of small TCR clusters suggested that some centripetal F-actin flow continued in the stable synapse. How can one define a lamellipodium quantitatively? The Sheetz and Wiggins labs developed methods based on loading cells with a fluorescent dye that fills the cytoplasm and then use TIRFM to image the dynamic footprints of the cell. Edge tracking algorithms quantify the advances and retraction of the edges and modify this to compensate for rapid movement of lymphocytes forming kinapses. This data can then be subjected to graphic and correlation analysis to compare the contact

ters continue to form in the periphery (Varma et al., 2006). These small TCR microclusters forming later during stimulation are invisible to wide-field imaging on bilayers or cell-cell system. In fact, the continual formation of small microclusters to sustain signaling has only recently been observed in cell-cell systems using a combination of laser tweezers and spinning disk confocal microscopy (Oddos et al., 2008). This sustained movement of small TCR clusters suggested that some centripetal F-actin flow continued in the stable synapse. How can one define a lamellipodium quantitatively? The Sheetz and Wiggins labs developed methods based on loading cells with a fluorescent dye that fills the cytoplasm and then use TIRFM to image the dynamic footprints of the cell. Edge tracking algorithms quantify the advances and retraction of the edges and modify this to compensate for rapid movement of lymphocytes forming kinapses. This data can then be subjected to graphic and correlation analysis to compare the contact area dynamics between cell types (Dobereiner et al., 2006; Sims et al., 2007). Our collaborative studies revealed that the outer edge of the immunological synapse displayed an evolutionarily conserved dynamic pattern of movement referred to as contractile oscillations (Fig 1). This is thought to emerge from cycles of F-actin polymerization and myosin II dependent contraction that periodically pull the membrane protrusion up and back. This is an excellent way to test the mechanical properties of the surface on which cells are interacting. This protrusion and retraction cycle then propagates as a wave around the entire periphery of the cell. These experiments provided strong quantitative evidence the periphery of primary mouse T cells forming synapses or kinapses on planar bilayers with MHC-pepide complexes, ICAM-1 and CD80 form a radial lamellipodium. More recently, Vale and my lab used speckle microscopy to explicitly demonstrate centripetal actin flow in the dSMAC and pSMAC regions (Kaizuka et al., 2007). T

area dynamics between cell types (Dobereiner et al., 2006; Sims et al., 2007). Our collaborative studies revealed that the outer edge of the immunological synapse displayed an evolutionarily conserved dynamic pattern of movement referred to as contractile oscillations (Fig 1). This is thought to emerge from cycles of F-actin polymerization and myosin II dependent contraction that periodically pull the membrane protrusion up and back. This is an excellent way to test the mechanical properties of the surface on which cells are interacting. This protrusion and retraction cycle then propagates as a wave around the entire periphery of the cell. These experiments provided strong quantitative evidence the periphery of primary mouse T cells forming synapses or kinapses on planar bilayers with MHC-pepide complexes, ICAM-1 and CD80 form a radial lamellipodium. More recently, Vale and my lab used speckle microscopy to explicitly demonstrate centripetal actin flow in the dSMAC and pSMAC regions (Kaizuka et al., 2007). This F-actin flow is a consequence of the polymerization of F-actin at the protruding edge, which is pushed backwards because the outer edge advances more slowly than actin is added to the growing filament ends. TCR microclusters are transported at about 40% of the speed of the F-actin in the lamellipodium. This suggests that the microclusters bind and dissociate from the actin network. This notion is also supported by studies showing that TCR clusters can navigate around barriers placed in planar bilayers by nanofabrication methods (DeMond et al., 2008). The ability to move around the barriers appears to depend upon periods of transport punctuated by diffusive movement, which allows the microcluster to make progress around diagonal barriers. TCR microcluster transport, contractile oscillations and centripetal F-actin flow support the model that immunological synapses are based on maintaining a radially symmetrical lamellipodium-the same structure Kupfer described as a dSMAC (Freiberg et al., 2002). The dSMAC

his F-actin flow is a consequence of the polymerization of F-actin at the protruding edge, which is pushed backwards because the outer edge advances more slowly than actin is added to the growing filament ends. TCR microclusters are transported at about 40% of the speed of the F-actin in the lamellipodium. This suggests that the microclusters bind and dissociate from the actin network. This notion is also supported by studies showing that TCR clusters can navigate around barriers placed in planar bilayers by nanofabrication methods (DeMond et al., 2008). The ability to move around the barriers appears to depend upon periods of transport punctuated by diffusive movement, which allows the microcluster to make progress around diagonal barriers. TCR microcluster transport, contractile oscillations and centripetal F-actin flow support the model that immunological synapses are based on maintaining a radially symmetrical lamellipodium-the same structure Kupfer described as a dSMAC (Freiberg et al., 2002). The dSMAC was reported as having a high concentration of both CD4 and CD45, but TIRFM imaging of these structures on bilayers does not consistently show this. It is likely that the impression of increased CD4 or CD45 in wide-field imaging is based on the lamellipodium having two plasma membrane layers separated by only 100–200 nm of cytoplasmic and thus appearing twice as bright as surrounding single membrane layers in the pSMAC. In fact, by TIRFM CD45 appears relatively uniform in the synapse except for discrete areas of exclusion around TCR microclusters (Varma et al., 2006). Thus, dSMAC is immunological shorthand for a radial lamellipodium. The pSMAC must also maintain radial symmetry to have a stable synapse because this structure contains most of the integrins that generate traction for movement (Sims et al., 2007). If the symmetry of the pSMAC is broken the cell will migrate, even if a radially symmetrical dSMAC appears to be maintained. The precise mechanism by which symmetry is established or broken is poorly u

was reported as having a high concentration of both CD4 and CD45, but TIRFM imaging of these structures on bilayers does not consistently show this. It is likely that the impression of increased CD4 or CD45 in wide-field imaging is based on the lamellipodium having two plasma membrane layers separated by only 100–200 nm of cytoplasmic and thus appearing twice as bright as surrounding single membrane layers in the pSMAC. In fact, by TIRFM CD45 appears relatively uniform in the synapse except for discrete areas of exclusion around TCR microclusters (Varma et al., 2006). Thus, dSMAC is immunological shorthand for a radial lamellipodium. The pSMAC must also maintain radial symmetry to have a stable synapse because this structure contains most of the integrins that generate traction for movement (Sims et al., 2007). If the symmetry of the pSMAC is broken the cell will migrate, even if a radially symmetrical dSMAC appears to be maintained. The precise mechanism by which symmetry is established or broken is poorly understood. We know that on the supported planar bilayer system WASP is required to maintain a stable synapse and PKC-θ contributes to symmetry breaking (Sims et al., 2007). Symmetry breaking in the contact plane leads to polarity and in a migrating cells this process is based two opposing actin-myosin networks-the lamellipodium dominated by Rac and a high F-actin:myosin II ratio and the uropod dominated by Rho and a low F-actin:myosin II ratio (Xu et al., 2003). Thus, we have speculated that myosin II may be a target in symmetry breaking. PKC-θ phosphorylates WASP interacting protein (WIP) and regulates its interaction with myosin II (Krzewski et al., 2006). WASP also interacts with this complex. One hypothesis is that myosin II activation via WIP phosphorylation leads to contraction of the pSMAC actin network leading to local thinning and breakdown, whereas WASP may either antagonize this myosin II activation or induced ventral actin polymerization to repair the pSMAC and restore symmetry after its been brok

nderstood. We know that on the supported planar bilayer system WASP is required to maintain a stable synapse and PKC-θ contributes to symmetry breaking (Sims et al., 2007). Symmetry breaking in the contact plane leads to polarity and in a migrating cells this process is based two opposing actin-myosin networks-the lamellipodium dominated by Rac and a high F-actin:myosin II ratio and the uropod dominated by Rho and a low F-actin:myosin II ratio (Xu et al., 2003). Thus, we have speculated that myosin II may be a target in symmetry breaking. PKC-θ phosphorylates WASP interacting protein (WIP) and regulates its interaction with myosin II (Krzewski et al., 2006). WASP also interacts with this complex. One hypothesis is that myosin II activation via WIP phosphorylation leads to contraction of the pSMAC actin network leading to local thinning and breakdown, whereas WASP may either antagonize this myosin II activation or induced ventral actin polymerization to repair the pSMAC and restore symmetry after its been broken. PKC-θ mediated synapse breaking seems like a negative feedback loop because the other major activity of PKC-θ in T cells is activation of NFkB and other transcription factors. Thus, the functional consequences of synapse stabilization as a result of PKC-θ inhibition can only be studied in pre-armed effector cells, which don’t need to activate transcription for function. The cSMAC was initially shown to contain PKC-θ and Lck, two kinases that are important for T cell activation (Monks et al., 1998). This suggested that the cSMAC might be involved in sustained signaling. Our early studies on planar bilayers demonstrated that TCR signaling was initiated before the cSMAC was formed based on cytoplasmic Ca2+ elevation at a time point where TCR-MHC-peptide interactions were focused in the periphery (Grakoui et al., 1999). This was more explicitly demonstrated with a specific phopho-Lck antibody, which revealed early TCR signaling in the periphery of the nascent synapse, but not at the cSMAC. This led to the sug

en. PKC-θ mediated synapse breaking seems like a negative feedback loop because the other major activity of PKC-θ in T cells is activation of NFkB and other transcription factors. Thus, the functional consequences of synapse stabilization as a result of PKC-θ inhibition can only be studied in pre-armed effector cells, which don’t need to activate transcription for function. The cSMAC was initially shown to contain PKC-θ and Lck, two kinases that are important for T cell activation (Monks et al., 1998). This suggested that the cSMAC might be involved in sustained signaling. Our early studies on planar bilayers demonstrated that TCR signaling was initiated before the cSMAC was formed based on cytoplasmic Ca2+ elevation at a time point where TCR-MHC-peptide interactions were focused in the periphery (Grakoui et al., 1999). This was more explicitly demonstrated with a specific phopho-Lck antibody, which revealed early TCR signaling in the periphery of the nascent synapse, but not at the cSMAC. This led to the suggestion that the cSMAC might be involved in signal termination (Lee et al., 2003). Computer models suggested that signals in response to weaker ligands might survive in the cSMAC due to a less aggressive attack by ubiquitin ligases. As discussed below this preservation of signaling in the cSMAC may also depend upon a reorganization of F-actin to fill in the normally F-actin depleted central area (Cemerski et al., 2008; Lee et al., 2003). The enigma with peripheral signaling in the immunological synapse was that TCR was not clearly associated with the signaling. This issue was resolved with TIRFM, which greatly increased the contrast of imaging of the cell-planar bilayer interface, as described above, but the discovery of the late submicron TCR microclusters that formed in the dSMAC and moved to the pSMAC over ~ 2 minutes. The movement of microcluster was interesting for what it said about actin dynamics, but the signaling behavior was even more interesting. Varma repeated the Valittuti experiment of blocking

gestion that the cSMAC might be involved in signal termination (Lee et al., 2003). Computer models suggested that signals in response to weaker ligands might survive in the cSMAC due to a less aggressive attack by ubiquitin ligases. As discussed below this preservation of signaling in the cSMAC may also depend upon a reorganization of F-actin to fill in the normally F-actin depleted central area (Cemerski et al., 2008; Lee et al., 2003). The enigma with peripheral signaling in the immunological synapse was that TCR was not clearly associated with the signaling. This issue was resolved with TIRFM, which greatly increased the contrast of imaging of the cell-planar bilayer interface, as described above, but the discovery of the late submicron TCR microclusters that formed in the dSMAC and moved to the pSMAC over ~ 2 minutes. The movement of microcluster was interesting for what it said about actin dynamics, but the signaling behavior was even more interesting. Varma repeated the Valittuti experiment of blocking signaling with anti-MHC while observing TCR microclusters and the cSMAC. He found that the TCR microclusters stopped forming and the last microclusters reached the cSMAC about 2 minutes after addition of the antibody, the exact time course with which Ca2+ signaling was eliminated (Varma et al., 2006). Thus, the cSMAC was unable to sustain TCR signaling beyond the 2 minute lifetime of the microclusters, although cSMAC interactions persisted for many minutes. These experiments implicated TCR microclusters in signaling by way of kinetics and complemented experiments that were performed subsequently demonstrating co-localization of TCR microclusters with signaling molecules including ZAP-70, LAT and SLP-76 in live cells and activated ZAP-70, LAT and Lck in fixed cells (Campi et al., 2005; Yokosuka et al., 2005). The movement of these microclusters was a clue to the cellular context of the activation process. How does the Jurkat T cell line model using solid phase anti-CD3 relate to work in primary cells using bon

signaling with anti-MHC while observing TCR microclusters and the cSMAC. He found that the TCR microclusters stopped forming and the last microclusters reached the cSMAC about 2 minutes after addition of the antibody, the exact time course with which Ca2+ signaling was eliminated (Varma et al., 2006). Thus, the cSMAC was unable to sustain TCR signaling beyond the 2 minute lifetime of the microclusters, although cSMAC interactions persisted for many minutes. These experiments implicated TCR microclusters in signaling by way of kinetics and complemented experiments that were performed subsequently demonstrating co-localization of TCR microclusters with signaling molecules including ZAP-70, LAT and SLP-76 in live cells and activated ZAP-70, LAT and Lck in fixed cells (Campi et al., 2005; Yokosuka et al., 2005). The movement of these microclusters was a clue to the cellular context of the activation process. How does the Jurkat T cell line model using solid phase anti-CD3 relate to work in primary cells using bona fide MHC-peptide ligands? Signaling of T cells in response to anti-CD3ε is not blocked by depolymerizatin of F-actin (Valitutti et al., 1995a). Similarly, knock-down of the WAVE2 complex completely eliminates lamellipodial F-actin, but doesn’t inhibit early T cell signaling (Nolz et al., 2006). All but the largest TCR microclusters formed with MHC-peptide ligands are dissolved by depolymerization of F-actin (Varma et al., 2006). Nonetheless, the spreading of Jurkat cells on surfaces coated by anti-CD3ε is accompanied by the formation of a dramatic lamellipodial F-actin ring (Bunnell et al., 2001) and the formation of many discrete TCR microclusters throughout the interface that require F-actin to form in the normal manner (Bunnell et al., 2002). These structures recruit ZAP-70 and SLP-76 and, interestingly, the SLP-76 foci dissociate from the ZAP-70 rich TCR clusters and stream toward the center of the interface based on a mixture of F-actin and microtubule dependent transport processes and appear to engage

a fide MHC-peptide ligands? Signaling of T cells in response to anti-CD3ε is not blocked by depolymerizatin of F-actin (Valitutti et al., 1995a). Similarly, knock-down of the WAVE2 complex completely eliminates lamellipodial F-actin, but doesn’t inhibit early T cell signaling (Nolz et al., 2006). All but the largest TCR microclusters formed with MHC-peptide ligands are dissolved by depolymerization of F-actin (Varma et al., 2006). Nonetheless, the spreading of Jurkat cells on surfaces coated by anti-CD3ε is accompanied by the formation of a dramatic lamellipodial F-actin ring (Bunnell et al., 2001) and the formation of many discrete TCR microclusters throughout the interface that require F-actin to form in the normal manner (Bunnell et al., 2002). These structures recruit ZAP-70 and SLP-76 and, interestingly, the SLP-76 foci dissociate from the ZAP-70 rich TCR clusters and stream toward the center of the interface based on a mixture of F-actin and microtubule dependent transport processes and appear to engage in sustained signaling even after internalization (Barr et al., 2006; Bunnell et al., 2006) Nguyen et al, 2008). This behavior is strikingly similar to the observed movement of MHC-peptide based TCR microclusters, which occurs in the plane of the plasma membrane in the synapse (Varma et al., 2006). However, the anti-CD3ε driven TCR clusters become systematically F-actin independent after formation (Douglass and Vale, 2005). The inclusion of β1 integrin ligands like fibronectin on the surface with anti-CD3ε results in stabilization of the SLP-76 interaction with the TCR clusters and also appears to dampen F-actin dynamics (Nguyen et al., 2008). Integrin ligands generally enhance TCR signaling (Shimizu et al., 1990) and this study suggests that one component of this effect may be stabilization of TCR signaling complexes. There are clearly differences between the polyvalent anti-CD3ε interaction with the TCR complex, which contains two copies of the CD3ε chain (Call et al., 2002), and the monovalent interaction

in sustained signaling even after internalization (Barr et al., 2006; Bunnell et al., 2006) Nguyen et al, 2008). This behavior is strikingly similar to the observed movement of MHC-peptide based TCR microclusters, which occurs in the plane of the plasma membrane in the synapse (Varma et al., 2006). However, the anti-CD3ε driven TCR clusters become systematically F-actin independent after formation (Douglass and Vale, 2005). The inclusion of β1 integrin ligands like fibronectin on the surface with anti-CD3ε results in stabilization of the SLP-76 interaction with the TCR clusters and also appears to dampen F-actin dynamics (Nguyen et al., 2008). Integrin ligands generally enhance TCR signaling (Shimizu et al., 1990) and this study suggests that one component of this effect may be stabilization of TCR signaling complexes. There are clearly differences between the polyvalent anti-CD3ε interaction with the TCR complex, which contains two copies of the CD3ε chain (Call et al., 2002), and the monovalent interaction of MHC-peptide ligands with TCR that change requirements for signaling. The transport process in the planar bilayers also creates a very useful lateral segregation of TCR based structures by age with the earliest TCR microclusters in the periphery and the oldest TCR clusters in the cSMAC. Recently, monovalent biotinylation of anti-CD3εhas created a means to achieve such tempero-spatial segregation of TCR signaling complexes by attaching anti-CD3 to planar bilayers with lipid anchored ICAM-1 to form classical synapses with Jurkat cells or polyclonal T cell populations (Kaizuka et al., 2007). This method has contributed to our understanding of the synapse dynamics. We have two quite different ways to study microclusters that are appropriate for different questions and have different degrees of difficulty. It is impossible to say that one is better than the other at this point-it depends upon the experiment. Further study of microclusters in T cell-DC interfaces using advanced confocal methodologies and even in

of MHC-peptide ligands with TCR that change requirements for signaling. The transport process in the planar bilayers also creates a very useful lateral segregation of TCR based structures by age with the earliest TCR microclusters in the periphery and the oldest TCR clusters in the cSMAC. Recently, monovalent biotinylation of anti-CD3εhas created a means to achieve such tempero-spatial segregation of TCR signaling complexes by attaching anti-CD3 to planar bilayers with lipid anchored ICAM-1 to form classical synapses with Jurkat cells or polyclonal T cell populations (Kaizuka et al., 2007). This method has contributed to our understanding of the synapse dynamics. We have two quite different ways to study microclusters that are appropriate for different questions and have different degrees of difficulty. It is impossible to say that one is better than the other at this point-it depends upon the experiment. Further study of microclusters in T cell-DC interfaces using advanced confocal methodologies and even in vivo will be needed to drill deeper into T cell signaling (Oddos et al., 2008). The relationship between TCR microclusters and F-actin suggests that the TCR clusters are formed actively rather than by diffusion trapping by ligand alone. The formation of TCR microclusters is F-actin dependent whether the ligand is a physiological MHC-peptide complex or a CD3 antibody (Bunnell et al., 2001; Campi et al., 2005; Douglass and Vale, 2005; Varma et al., 2006). This also extends to signaling because depolymerization of actin in an established synapse results in rapid cessation of signaling, but does not disrupt larger TCR microclusters or the cSMAC (Varma et al., 2006). The synapse contains a zone of F-actin depletion at the center, corresponding to the cSMAC regardless of whether this structure is filled with TCR (Kaizuka et al., 2007). When TCR clusters reach the actin free zone in the center the signaling process appears to be terminated. The mechanism of signal termination is not known, but may be as simple as t

vivo will be needed to drill deeper into T cell signaling (Oddos et al., 2008). The relationship between TCR microclusters and F-actin suggests that the TCR clusters are formed actively rather than by diffusion trapping by ligand alone. The formation of TCR microclusters is F-actin dependent whether the ligand is a physiological MHC-peptide complex or a CD3 antibody (Bunnell et al., 2001; Campi et al., 2005; Douglass and Vale, 2005; Varma et al., 2006). This also extends to signaling because depolymerization of actin in an established synapse results in rapid cessation of signaling, but does not disrupt larger TCR microclusters or the cSMAC (Varma et al., 2006). The synapse contains a zone of F-actin depletion at the center, corresponding to the cSMAC regardless of whether this structure is filled with TCR (Kaizuka et al., 2007). When TCR clusters reach the actin free zone in the center the signaling process appears to be terminated. The mechanism of signal termination is not known, but may be as simple as the inability to amplify signals in the absence of F-actin. It is not known how the TCR microclusters continue to move to the center of the synapse when the F-actin conveyor belt stops 1–2 μm from the center. This could be a diffusive process or might involve some alternative transport system that remains to be described. For example, the zone of F-actin depletion is observed in cytotoxic T cell synapses and allows close approach of the centrosome to the plasma membrane for efficient directed secretion (Stinchcombe et al., 2006). It is not clear why F-actin is so important for TCR signal transduction because anti-CD3 stimulation to Ca2+ mobilization and cytokine production doesn’t require intact F-actin (Valitutti et al., 1995a). Similarly, B cells require F-actin to recognize ligands on a surface, but not aggregating ligands in solution. Stimulation by surface presented ligands requires F-actin, Rap1 and CD19 (Depoil et al., 2008; Lin et al., 2008). The model for stimulation of activation of BCR by monovalent

he inability to amplify signals in the absence of F-actin. It is not known how the TCR microclusters continue to move to the center of the synapse when the F-actin conveyor belt stops 1–2 μm from the center. This could be a diffusive process or might involve some alternative transport system that remains to be described. For example, the zone of F-actin depletion is observed in cytotoxic T cell synapses and allows close approach of the centrosome to the plasma membrane for efficient directed secretion (Stinchcombe et al., 2006). It is not clear why F-actin is so important for TCR signal transduction because anti-CD3 stimulation to Ca2+ mobilization and cytokine production doesn’t require intact F-actin (Valitutti et al., 1995a). Similarly, B cells require F-actin to recognize ligands on a surface, but not aggregating ligands in solution. Stimulation by surface presented ligands requires F-actin, Rap1 and CD19 (Depoil et al., 2008; Lin et al., 2008). The model for stimulation of activation of BCR by monovalent ligands in supported planar bilayers is based on diffusion trapping of receptors and ligands in microdomains with multiple BCR and ligands. This mode of clustering is likely driven by F-actin dependent membrane fluctuations and adhesion, perhaps accounting for the role of F-actin in enhancing B cell recognition of solid phase ligands (Carrasco et al., 2004; Tolar et al., 2008). For T cells, the F-actin requirement seems to involve both forming microclusters and then formation of signaling complexes at the TCR clusters. This is based on the observation that many TCR microclusters are stable after F-actin depolymerization, but signaling is still terminated even though the receptor clusters persist. All antigen receptors engage in signaling that activates actin polymerization via the Rac and Cdc42 small G-proteins leading to activation of the WAVE2 complexes and WASp (Barda-Saad et al., 2005; Nolz et al., 2006). In the absence of WAVE2 the lamellipodium at the periphery of T cell contacts with anti-CD3 coated s

ligands in supported planar bilayers is based on diffusion trapping of receptors and ligands in microdomains with multiple BCR and ligands. This mode of clustering is likely driven by F-actin dependent membrane fluctuations and adhesion, perhaps accounting for the role of F-actin in enhancing B cell recognition of solid phase ligands (Carrasco et al., 2004; Tolar et al., 2008). For T cells, the F-actin requirement seems to involve both forming microclusters and then formation of signaling complexes at the TCR clusters. This is based on the observation that many TCR microclusters are stable after F-actin depolymerization, but signaling is still terminated even though the receptor clusters persist. All antigen receptors engage in signaling that activates actin polymerization via the Rac and Cdc42 small G-proteins leading to activation of the WAVE2 complexes and WASp (Barda-Saad et al., 2005; Nolz et al., 2006). In the absence of WAVE2 the lamellipodium at the periphery of T cell contacts with anti-CD3 coated surfaces is lost (Nolz et al., 2006). This does not alter that ability of these cells to initiate early TCR signaling in response to solid phase anti-CD3, but more work is needed to determine if this alters sensitivity to MHC-peptide ligands as expected. The recent focus on microclusters raises questions about cSMAC-associated signals. Is the cSMAC just for signal termination or is it a site of TCR or other relevant signaling? Is the cSMAC even one compartment? Kupfer defined the cSMAC based on accumulation of TCR and PKC-θ. Dynamic studies using fluorescence recovery after photobleaching (FRAP) revealed that TCR-MHC-peptide interactions are particularly stable in the cSMAC (Grakoui et al., 1999) and that the TCR microclusters that converge to form the cSMAC appear to fuse together into one stable structure on planar bilayers (Varma et al., 2006). This structure is partly shed by the T cell if it breaks the synapse and migrates or wanes over 10’s of minutes in stable synapses. Is this highly stabilized structu

urfaces is lost (Nolz et al., 2006). This does not alter that ability of these cells to initiate early TCR signaling in response to solid phase anti-CD3, but more work is needed to determine if this alters sensitivity to MHC-peptide ligands as expected. The recent focus on microclusters raises questions about cSMAC-associated signals. Is the cSMAC just for signal termination or is it a site of TCR or other relevant signaling? Is the cSMAC even one compartment? Kupfer defined the cSMAC based on accumulation of TCR and PKC-θ. Dynamic studies using fluorescence recovery after photobleaching (FRAP) revealed that TCR-MHC-peptide interactions are particularly stable in the cSMAC (Grakoui et al., 1999) and that the TCR microclusters that converge to form the cSMAC appear to fuse together into one stable structure on planar bilayers (Varma et al., 2006). This structure is partly shed by the T cell if it breaks the synapse and migrates or wanes over 10’s of minutes in stable synapses. Is this highly stabilized structure in which TCR seem to be shed or degraded all there is to the cSMAC? Analysis of CD28-CD80 interactions in the synapse suggests that there is a second, more dynamic component to the cSMAC that is typically not well resolved, but represents a very distinct sub-cellular compartment (Tseng et al., 2008; Yokosuka et al., 2008). CD28-CD80 interactions colocalize with TCR-MHC-peptide interactions in microclusters. When these mixed microclusters reach the cSMAC, mostof the TCR are incorporated into a stable central cluster, but all of the CD28 remains in an intermediate compartments which is very dynamic and appears to be critical for sustained PKC-θ signaling (Yokosuka et al., 2008). This annular structure sits at the inside edge of the F-actin rich lamella and thus the small amounts of TCR in this compartment may continue to signal to maintain the dynamic CD28-CD80 interactions. Similar segregation of TCR and CD28 is observed in T cell-DC interfaces, although it was not possible to observe the precursor microclu

re in which TCR seem to be shed or degraded all there is to the cSMAC? Analysis of CD28-CD80 interactions in the synapse suggests that there is a second, more dynamic component to the cSMAC that is typically not well resolved, but represents a very distinct sub-cellular compartment (Tseng et al., 2008; Yokosuka et al., 2008). CD28-CD80 interactions colocalize with TCR-MHC-peptide interactions in microclusters. When these mixed microclusters reach the cSMAC, mostof the TCR are incorporated into a stable central cluster, but all of the CD28 remains in an intermediate compartments which is very dynamic and appears to be critical for sustained PKC-θ signaling (Yokosuka et al., 2008). This annular structure sits at the inside edge of the F-actin rich lamella and thus the small amounts of TCR in this compartment may continue to signal to maintain the dynamic CD28-CD80 interactions. Similar segregation of TCR and CD28 is observed in T cell-DC interfaces, although it was not possible to observe the precursor microclusters (Tseng et al., 2008). Blocking TCR signaling with anti-MHC-peptide antibodies rapidly eliminated the bright CD28-CD80 foci, consistent with a continual role for TCR signaling in maintaining this component of the cSMAC. These studies demonstrate that the cSMAC consists of two compartments: one a stable structure enriched in non-signaling TCR destined for shedding or degradation (a) and one highly dynamic structure rich in F-actin, CD28 and PKC-θ (b) (table 1). These compartments are difficult to resolve in cSMACs formedin cell-cell interfaces. The mechanisms by which CD28 and TCR are segregated into these two cSMAC compartments is not known. The mechanism of TCR triggering has been an enduring problem. The prevailing model has been based on TCR dimerization or clustering as a triggering modality (Germain, 1997; Weiss and Littman, 1994). This is largely based on models from receptor tyrosine kinases and observations that antibody crosslinking triggers signaling. However, the is an adapter that recruits no

sters (Tseng et al., 2008). Blocking TCR signaling with anti-MHC-peptide antibodies rapidly eliminated the bright CD28-CD80 foci, consistent with a continual role for TCR signaling in maintaining this component of the cSMAC. These studies demonstrate that the cSMAC consists of two compartments: one a stable structure enriched in non-signaling TCR destined for shedding or degradation (a) and one highly dynamic structure rich in F-actin, CD28 and PKC-θ (b) (table 1). These compartments are difficult to resolve in cSMACs formedin cell-cell interfaces. The mechanisms by which CD28 and TCR are segregated into these two cSMAC compartments is not known. The mechanism of TCR triggering has been an enduring problem. The prevailing model has been based on TCR dimerization or clustering as a triggering modality (Germain, 1997; Weiss and Littman, 1994). This is largely based on models from receptor tyrosine kinases and observations that antibody crosslinking triggers signaling. However, the is an adapter that recruits non-receptor tyrosine kinases to 10 docking sites, the immunotyrosine based activation motifs (ITAMs), in response to ligand binding. With all these docking sites, it is not clear that dimerizing this receptor would increase its activity. Recent studies have provided indirect evidence that monovalent ligands can trigger TCR microclusters and signaling events without directly cross-linking the receptor to form dimers e.g.(Varma et al., 2006). It is interesting at this point to think about how the TCR would sense such a monovalent engagement event? Recent data from the BCR and TCR systems provide insights into accessibility changes in cytoplasmic domains of the receptor during triggering and provide raw material for a draft model that incorporates an early role for F-actin. The BCR has two signal transduction subunits with one ITAM in each. BCR with a FRET donor at the C-terminus of transmembrane immunoglobulin (sIg) and a FRET acceptor on the C-terminus of Igα have a high FRET signal in the basal, non-signaling

n-receptor tyrosine kinases to 10 docking sites, the immunotyrosine based activation motifs (ITAMs), in response to ligand binding. With all these docking sites, it is not clear that dimerizing this receptor would increase its activity. Recent studies have provided indirect evidence that monovalent ligands can trigger TCR microclusters and signaling events without directly cross-linking the receptor to form dimers e.g.(Varma et al., 2006). It is interesting at this point to think about how the TCR would sense such a monovalent engagement event? Recent data from the BCR and TCR systems provide insights into accessibility changes in cytoplasmic domains of the receptor during triggering and provide raw material for a draft model that incorporates an early role for F-actin. The BCR has two signal transduction subunits with one ITAM in each. BCR with a FRET donor at the C-terminus of transmembrane immunoglobulin (sIg) and a FRET acceptor on the C-terminus of Igα have a high FRET signal in the basal, non-signaling state. Remarkably, triggering results in a rapid decrease in the FRET signal, suggesting an “opening” of the complex (Tolar et al., 2005). It is not known what conformational change causes this decreased FRET. One interpretation is based on the model that the ITAMs may interact with the membrane prior to triggering, making the tyrosine inaccessible to kinases and preventing signaling (Aivazian and Stern, 2000). The interaction with the membrane would confine the FRET acceptor associated with the C-terminus of the ITAM bearing subunit to the membrane in proximity to the FRET donor that is kept close to the membrane by the short sIg cytoplasmic domain. Triggering would then involve dissociation of the ITAM from the membrane. A recent study using live cell FRET imaging and structure determination supports the idea that ITAM displacement from the membrane is a critical step in triggering (Xu et al., 2008). This study found that each ITAM in the TCR has a positively charged motif on its N-terminal side that intera

state. Remarkably, triggering results in a rapid decrease in the FRET signal, suggesting an “opening” of the complex (Tolar et al., 2005). It is not known what conformational change causes this decreased FRET. One interpretation is based on the model that the ITAMs may interact with the membrane prior to triggering, making the tyrosine inaccessible to kinases and preventing signaling (Aivazian and Stern, 2000). The interaction with the membrane would confine the FRET acceptor associated with the C-terminus of the ITAM bearing subunit to the membrane in proximity to the FRET donor that is kept close to the membrane by the short sIg cytoplasmic domain. Triggering would then involve dissociation of the ITAM from the membrane. A recent study using live cell FRET imaging and structure determination supports the idea that ITAM displacement from the membrane is a critical step in triggering (Xu et al., 2008). This study found that each ITAM in the TCR has a positively charged motif on its N-terminal side that interacts with acidic phospholipids in the inner leaflet and facilitates the docking of both tyrosines in the lipid bilayer where they cannot be phosphorylated. The results suggest that a change in the lipid environment to a more neutral composition is needed for ITAM access by Src family kinases (Douglass and Vale, 2005). How could a single MHC-peptide complex change the lipid environment of the TCR? Our understanding of the basal distribution of the TCR is constrained by two seemingly contradictory results: evidence for preclustering from electron microscopy (Schamel et al., 2005) and non-correlated monomeric diffusion using fluorescence correlation spectroscopy (James et al., 2007). Long term tracking of Fce receptor movements in the context of actin bundles on rat basophilic leukemia cells shows that receptors can be corralled by actin and diffuse independently at the same time (Andrews et al., 2008). These results suggest that the clusters seen in EM maybe a result of transient confinement on monomeric recepto

cts with acidic phospholipids in the inner leaflet and facilitates the docking of both tyrosines in the lipid bilayer where they cannot be phosphorylated. The results suggest that a change in the lipid environment to a more neutral composition is needed for ITAM access by Src family kinases (Douglass and Vale, 2005). How could a single MHC-peptide complex change the lipid environment of the TCR? Our understanding of the basal distribution of the TCR is constrained by two seemingly contradictory results: evidence for preclustering from electron microscopy (Schamel et al., 2005) and non-correlated monomeric diffusion using fluorescence correlation spectroscopy (James et al., 2007). Long term tracking of Fce receptor movements in the context of actin bundles on rat basophilic leukemia cells shows that receptors can be corralled by actin and diffuse independently at the same time (Andrews et al., 2008). These results suggest that the clusters seen in EM maybe a result of transient confinement on monomeric receptors. Basal fluctuations in TCR density were observed as highly dynamic structures similar in size to microclusters, but which could not be tracked from one frame to the next (Varma et al., 2006). In order to maintain low basal activity the membrane domains in which the TCR moves prior to ligand binding will likely be highly acidic and fluid. The lamellipodium is a relatively flat membrane region with a dense mesh of branched actin filaments translocating away from the leading edge (Svitkina et al., 1997). The mesh size of the actin gel if relatively fine, with interstitial areas on the order of 100 nm based on electron microscopy analysis of model lamellipodia (Svitkina et al., 1997). This F-actin mesh is similar in scale to the lipids domains that have been identified in membranes as lipid rafts (Sharma et al., 2004). The spatial distribution of acidic lipids like PS on the inner leaflet is not known, but structural constrains suggest that liquid ordered domains should be enriched in neutral phosphatidylethan

rs. Basal fluctuations in TCR density were observed as highly dynamic structures similar in size to microclusters, but which could not be tracked from one frame to the next (Varma et al., 2006). In order to maintain low basal activity the membrane domains in which the TCR moves prior to ligand binding will likely be highly acidic and fluid. The lamellipodium is a relatively flat membrane region with a dense mesh of branched actin filaments translocating away from the leading edge (Svitkina et al., 1997). The mesh size of the actin gel if relatively fine, with interstitial areas on the order of 100 nm based on electron microscopy analysis of model lamellipodia (Svitkina et al., 1997). This F-actin mesh is similar in scale to the lipids domains that have been identified in membranes as lipid rafts (Sharma et al., 2004). The spatial distribution of acidic lipids like PS on the inner leaflet is not known, but structural constrains suggest that liquid ordered domains should be enriched in neutral phosphatidylethanolamine (Brown and London, 2000). I would speculate that TCR maybe confined to approximately 10% of the plasma membrane composed of disordered, fluid phase and acidic lipids, which are corralled by the mobile actin elements. In the basal state the TCR cannot be individually transported into less acidic liquid ordered domains (Fig 2). Clustering of the receptors by serial ligand binding can stabilize the interaction with the F-actin meshwork and create a sufficient force to overcome resistance to entry into less acidic domains, in which the ITAMs are exposed in the presence of Src family kinases and with depletion of CD45 together lead to triggering of the signaling cascade (Fig 2). It is likely the the “lipid rafts” also anchored to disctinct cortical actin networks and this actin may anchor these domains against movement by the dendritic actin network inivolved in the retrograde flow (Chichili and Rodgers, 2007). This model invokes shearing action of the lamellipodial actin to generate force to overcome ener

olamine (Brown and London, 2000). I would speculate that TCR maybe confined to approximately 10% of the plasma membrane composed of disordered, fluid phase and acidic lipids, which are corralled by the mobile actin elements. In the basal state the TCR cannot be individually transported into less acidic liquid ordered domains (Fig 2). Clustering of the receptors by serial ligand binding can stabilize the interaction with the F-actin meshwork and create a sufficient force to overcome resistance to entry into less acidic domains, in which the ITAMs are exposed in the presence of Src family kinases and with depletion of CD45 together lead to triggering of the signaling cascade (Fig 2). It is likely the the “lipid rafts” also anchored to disctinct cortical actin networks and this actin may anchor these domains against movement by the dendritic actin network inivolved in the retrograde flow (Chichili and Rodgers, 2007). This model invokes shearing action of the lamellipodial actin to generate force to overcome energetic barriers, similar to recent models for the role of lateral mechanical forces in integrin activation (Zhu et al., 2008). The specific adapters that link TCR to F-actin are not well described. The complex may include NCK, SLP-76, ADAP, SKAP55, EVL, Vav, Rac, Cdc42 and WASP certainly may play a role once signaling is initiated (Barda-Saad et al., 2005; Bubeck Wardenburg et al., 1998; Krause et al., 2000). It has also been suggested that ZAP-70 may play a role through binding of ezrin (Ilani et al., 2007). It appears that TCR signaling in microclusters ceases when the microcluster reaches the actin depleted cSMAC. Since activated TCR appear equipped to generate their own dynamic actin focus, the suppression of this mode of actin dymanics in the cSMAC is likely to be active, rather than a passive dissipation of lamellar actin. Less is known about the basal interactions of TCR with actin that might be available to stabilize a cluster early in the triggering process. This is likely a complex situation. An exam

getic barriers, similar to recent models for the role of lateral mechanical forces in integrin activation (Zhu et al., 2008). The specific adapters that link TCR to F-actin are not well described. The complex may include NCK, SLP-76, ADAP, SKAP55, EVL, Vav, Rac, Cdc42 and WASP certainly may play a role once signaling is initiated (Barda-Saad et al., 2005; Bubeck Wardenburg et al., 1998; Krause et al., 2000). It has also been suggested that ZAP-70 may play a role through binding of ezrin (Ilani et al., 2007). It appears that TCR signaling in microclusters ceases when the microcluster reaches the actin depleted cSMAC. Since activated TCR appear equipped to generate their own dynamic actin focus, the suppression of this mode of actin dymanics in the cSMAC is likely to be active, rather than a passive dissipation of lamellar actin. Less is known about the basal interactions of TCR with actin that might be available to stabilize a cluster early in the triggering process. This is likely a complex situation. An example of the potential complexity can be seen in interaction networks recently compiled as the integrin adhesome (Zaidel-Bar et al., 2007). Once the ITAMs are exposed Src family kinases can then initiate phosphorylation by diffusion into the same domain (Douglass and Vale, 2005)(Fig 2). Exclusion of CD45 in the nascent foci would increase the half-life of the phosphorylated ITAM allowing sufficient time for ZAP-70 recruitment (Varma et al., 2006). This cluster may interact more strongly with LAT so that ZAP-70 could phosphorylate LAT and Itk to initiate PLC-g recruitment and initiation of Ca2+ signaling, PKC activation and Ras-GRP recruitment. Integrin microclusters will be interspersed with the TCR microclusters. Integrin dependent signaling will generate additional diacylglycerol for RasGRP by activating phospholipase D and phosphatidic acid phosphatase (Mor et al., 2007). Electron micrographs of membrane sheets suggest that immunoreceptor rich and LAT rich islands only partially mix (Lillemeier et al., 2006;

ple of the potential complexity can be seen in interaction networks recently compiled as the integrin adhesome (Zaidel-Bar et al., 2007). Once the ITAMs are exposed Src family kinases can then initiate phosphorylation by diffusion into the same domain (Douglass and Vale, 2005)(Fig 2). Exclusion of CD45 in the nascent foci would increase the half-life of the phosphorylated ITAM allowing sufficient time for ZAP-70 recruitment (Varma et al., 2006). This cluster may interact more strongly with LAT so that ZAP-70 could phosphorylate LAT and Itk to initiate PLC-g recruitment and initiation of Ca2+ signaling, PKC activation and Ras-GRP recruitment. Integrin microclusters will be interspersed with the TCR microclusters. Integrin dependent signaling will generate additional diacylglycerol for RasGRP by activating phospholipase D and phosphatidic acid phosphatase (Mor et al., 2007). Electron micrographs of membrane sheets suggest that immunoreceptor rich and LAT rich islands only partially mix (Lillemeier et al., 2006; Wilson et al., 2001). The force needed to induce island mixing may be generated by periodic myosin II based contraction. This may account for the role of myosin IIA in the signal amplification from Lck, which is normally activated after myosin IIA knock-down, to ZAP-70 and LAT, which are only weakly activated in myosin IIA knock-down T cells (Ilani et al., 2009). The TCR triggering process in microclusters and how this is sustained in a synapse has relevance to T cell decision-making. T cell differentiation is controlled in large part by cytokines and small molecules from APC. There are two independent reports that propose distinct mechanisms for the synapse to influence differentiation. One is the concentration of interferon-γ receptors in the synapse leading to increased T helper 1 (Th1) cell development (Maldonado et al., 2004). IL-4 counteracts this through Stat6 (Maldonado et al., 2004). The other is the control of polarity networks leading to asymmetric cell division to control memory-effector decision

Wilson et al., 2001). The force needed to induce island mixing may be generated by periodic myosin II based contraction. This may account for the role of myosin IIA in the signal amplification from Lck, which is normally activated after myosin IIA knock-down, to ZAP-70 and LAT, which are only weakly activated in myosin IIA knock-down T cells (Ilani et al., 2009). The TCR triggering process in microclusters and how this is sustained in a synapse has relevance to T cell decision-making. T cell differentiation is controlled in large part by cytokines and small molecules from APC. There are two independent reports that propose distinct mechanisms for the synapse to influence differentiation. One is the concentration of interferon-γ receptors in the synapse leading to increased T helper 1 (Th1) cell development (Maldonado et al., 2004). IL-4 counteracts this through Stat6 (Maldonado et al., 2004). The other is the control of polarity networks leading to asymmetric cell division to control memory-effector decisions (Chang et al., 2007; Ludford-Menting et al., 2005). A particular challenge is in understanding how the microcluster-based mechanism sustains signaling from small numbers of ligand to drive differentiation. If each microcluster can sustain signaling for 2 minutes as the microclusters translocates from the periphery to the cSMAC. How is signaling sustained with only 10 MHC-peptide complexes? An interesting observation is that although the actin depleted zone at the center of the synapse is always present, the size of the cSMAC is linearly dependent upon the MHC-peptide density such that no TCR cSMAC if formed at the lower limit of MHC-peptide density. Under these conditions our model would posit that MHC-peptide ligand are recycled expensively by long term serial triggering at the F-actin rich cSMAC-pSMAC boundary. This fits with notions of serial triggering initially propose by Valittuti and Lanzavechia (Valitutti et al., 1995b), but would induce very little if any TCR down-regulation because all receptors a

s (Chang et al., 2007; Ludford-Menting et al., 2005). A particular challenge is in understanding how the microcluster-based mechanism sustains signaling from small numbers of ligand to drive differentiation. If each microcluster can sustain signaling for 2 minutes as the microclusters translocates from the periphery to the cSMAC. How is signaling sustained with only 10 MHC-peptide complexes? An interesting observation is that although the actin depleted zone at the center of the synapse is always present, the size of the cSMAC is linearly dependent upon the MHC-peptide density such that no TCR cSMAC if formed at the lower limit of MHC-peptide density. Under these conditions our model would posit that MHC-peptide ligand are recycled expensively by long term serial triggering at the F-actin rich cSMAC-pSMAC boundary. This fits with notions of serial triggering initially propose by Valittuti and Lanzavechia (Valitutti et al., 1995b), but would induce very little if any TCR down-regulation because all receptors are needed for sensitive recognition of rare MHC-peptide ligands. The links between TCR signaling and polarity networks include Cdc42 and PKC-ζ. Activation of Cdc42 has been extensively studied in T cells due to interest in immunodeficiencies such as Wiscott-Alrdrich Syndrome. PKC-ζ can be activated in the Par3-Par6 complex by activation of Cdc42, but it is not clear what it means that PKC-ζ is concentrated in the distal pole complex, the part of the T cell farthest from the synapse (Chang et al., 2007). The polarity networks control the positioning of actin, microtubules and intermediate filament and spindles. The dynamic F-actin networks and myosin II seem important at early stages of signaling complex assembly. The actin-myosin system is critical for multiple stages in TCR triggering and sustained signaling. It will be exciting in the future to determine in more detail how the context of TCR signaling allows this process to shape differentiation in parallel with powerful innate signals. I thank Kaushik Chou

re needed for sensitive recognition of rare MHC-peptide ligands. The links between TCR signaling and polarity networks include Cdc42 and PKC-ζ. Activation of Cdc42 has been extensively studied in T cells due to interest in immunodeficiencies such as Wiscott-Alrdrich Syndrome. PKC-ζ can be activated in the Par3-Par6 complex by activation of Cdc42, but it is not clear what it means that PKC-ζ is concentrated in the distal pole complex, the part of the T cell farthest from the synapse (Chang et al., 2007). The polarity networks control the positioning of actin, microtubules and intermediate filament and spindles. The dynamic F-actin networks and myosin II seem important at early stages of signaling complex assembly. The actin-myosin system is critical for multiple stages in TCR triggering and sustained signaling. It will be exciting in the future to determine in more detail how the context of TCR signaling allows this process to shape differentiation in parallel with powerful innate signals. I thank Kaushik Choudhuri and David Fooksman for valuable discussions. Due to length constraints not all relevant literature could be cited and I apologize in advance regarding omissions. This work was supported by NIH grants AI43542and the PN2 EY016586, a Nanomedicine Development Center.

dhuri and David Fooksman for valuable discussions. Due to length constraints not all relevant literature could be cited and I apologize in advance regarding omissions. This work was supported by NIH grants AI43542and the PN2 EY016586, a Nanomedicine Development Center.

A hydrologic reconnaissance of the Medicine Lake Volcano area was done to collect data needed for the design of a hydrologic monitoring plan. The reconnaissance was completed during two field trips made in June and September 1992, during which geothermal and hydrologic features of public interest in the Medicine Lake area were identified. Selected wells, springs, and geothermal features were located and documented, and initial water-level, discharge, temperature, and specific-conductance measurements were made. Lakes in the study area also were surveyed during the September field trip. Temperature, specific- conductance, dissolved oxygen, and pH data were collected by using a multiparameter probe. The proposed monitoring plan includes measurement of water levels in wells, discharge from springs, and lake stage, as well as analysis of well-,spring-, and lake-water quality. In determining lake-water quality, data for both stratified and unstratified conditions would be considered. (Data for stratified conditions were collected during the reconnaissance phase of this project, but data for unstratified conditions were not.) In addition, lake stage also would be monitored. A geothermal feature near Medicine Lake is a "hot spot" from which hot gases discharge from two distinct vents. Gas chemistry and temperature would be monitored in one of these vents. Additional publication details USGS Numbered Series Hydrologic data and description of a hydrologic monitoring plan for Medicine Lake Volcano, California U.S. Geological Survey ; Information Services [distributor],

Key Safe Routes to School Research Practitioners implementing Safe Routes to School programs, or other active travel promotion programs, have a large scope of issues to address. This section is a collection of research that evaluates current Safe Routes to School programs and identifies issues to consider when implementing new programs. Findings from these studies can provide insight into the cost-effectiveness of programs, impact of school siting, and how gender and socio-demographic factors can influence active travel to school. Also included in this section is academic literature reviewing legislative policies that can provide practitioners with information regarding potential funding opportunities and policy trends that influence active transport initiatives. Many of the articles in this section directly reference Safe Routes to School programs. - Safe Routes to School programs have shown a 37 percent increase in bicycling and walking where projects have been undertaken. (Stewart, 2014) - Specific to Safe Routes to School, introducing a program focused on education and encouragement increased bicycling to school by 5 percent each year. When programs also incorporated infrastructure improvements like sidewalks, crosswalks and covered bicycle parking, the rate of bicycling and walking improved to between 5 percent and 20 percent (McDonald, 2013). - One study reports that the national Safe Routes to School program has the potential to positively influence individuals, communities, and the environment regardless of race, ethnicity, or socioeconomic status by providing funds to address some of the barriers and improve the ability of students to safely walk and bicycle to school (Martin, et al., 2008). - The findings of an analysis of walking and biking to school among low-income and minority youth in the United States has significant implications, reporting that Safe Routes to School programs have the potential to strongly benefit minority and low-income students, especially because many of those students are more

Routes to School, introducing a program focused on education and encouragement increased bicycling to school by 5 percent each year. When programs also incorporated infrastructure improvements like sidewalks, crosswalks and covered bicycle parking, the rate of bicycling and walking improved to between 5 percent and 20 percent (McDonald, 2013). - One study reports that the national Safe Routes to School program has the potential to positively influence individuals, communities, and the environment regardless of race, ethnicity, or socioeconomic status by providing funds to address some of the barriers and improve the ability of students to safely walk and bicycle to school (Martin, et al., 2008). - The findings of an analysis of walking and biking to school among low-income and minority youth in the United States has significant implications, reporting that Safe Routes to School programs have the potential to strongly benefit minority and low-income students, especially because many of those students are more likely to live near the school they attend (McDonald, 2008). - The odds of walking and bicycling to school are 40% lower in girls than in boys (McMillan, et al., 2006). - Results show that children who pass completed Safe Routes to School projects are more likely to show increases in walking or bicycle travel than are children who do not pass by projects (15% vs. 4%), supporting the effectiveness of Safe Routes to School construction projects (Boarnet, et al., 2005). - A review of the success of the Safe Routes to School program in Marin County reports a 64% increase in the number of children walking to school, a 114% increase in the number of students biking, and a 91% increase in the number of students carpooling (Staunton, et al., 2003). Academic Research Articles and Findings: - State-level school physical activity policies are currently not implemented on a broad level, often have weak and non-specific language, and may not effectively monitor implementation. - At the time of study, only 16 states had p

likely to live near the school they attend (McDonald, 2008). - The odds of walking and bicycling to school are 40% lower in girls than in boys (McMillan, et al., 2006). - Results show that children who pass completed Safe Routes to School projects are more likely to show increases in walking or bicycle travel than are children who do not pass by projects (15% vs. 4%), supporting the effectiveness of Safe Routes to School construction projects (Boarnet, et al., 2005). - A review of the success of the Safe Routes to School program in Marin County reports a 64% increase in the number of children walking to school, a 114% increase in the number of students biking, and a 91% increase in the number of students carpooling (Staunton, et al., 2003). Academic Research Articles and Findings: - State-level school physical activity policies are currently not implemented on a broad level, often have weak and non-specific language, and may not effectively monitor implementation. - At the time of study, only 16 states had policies on minutes of physical activity during the school day/week or minutes or percent of physical education to be spent in physical activity. - No policies were rated as having strong wording, defined in this study as specifying moderate-to-vigorous physical activity (MVPA) and wording on implementation and monitoring. - This research study examined state-level policies collected by the RJWF Bridging the Gap (BTG) program in 2011. Policies were rated as weak, moderate, and strong in specifying minutes of physical activity in physical education or during school. - The researchers also interviewed state-level physical education coordinators about implementation, monitoring, and enforcement of policies. Carlson JA, Sallis JF, Chriqui JF, Schneider L, McDermid LC, Agron P. (2013). State policies about physical activity minutes in physical education or during school. Journal of School Health 83, 150-156. - Comprehensive physical activity programs in school settings can affect physical activity, health, and acad

olicies on minutes of physical activity during the school day/week or minutes or percent of physical education to be spent in physical activity. - No policies were rated as having strong wording, defined in this study as specifying moderate-to-vigorous physical activity (MVPA) and wording on implementation and monitoring. - This research study examined state-level policies collected by the RJWF Bridging the Gap (BTG) program in 2011. Policies were rated as weak, moderate, and strong in specifying minutes of physical activity in physical education or during school. - The researchers also interviewed state-level physical education coordinators about implementation, monitoring, and enforcement of policies. Carlson JA, Sallis JF, Chriqui JF, Schneider L, McDermid LC, Agron P. (2013). State policies about physical activity minutes in physical education or during school. Journal of School Health 83, 150-156. - Comprehensive physical activity programs in school settings can affect physical activity, health, and academic performance. - Students participate in much of their physical activity through physical education classes, but schools can help increase students’ activity levels by strengthening curriculum and increasing opportunities outside these classes. - State and school district wellness policies should include stronger goals and requirements for daily physical activity. - Joint use agreements can encourage physical activity after school and on weekends, especially in low-income, inner-city, and rural areas with fewer recreational facilities. - This research synthesis summarizes evidence about different ways schools can promote physical activity. Ward, D.S. (2011). School Policies on Physical Education and Physical Activity: A Research Synthesis. Active Living Research. - Measuring the built environment can help assess needs and set priorities for creating healthy community design. - The built environment includes buildings, roads, sidewalks, utilities, homes, transit, fixtures, parks and all other man-made entit

emic performance. - Students participate in much of their physical activity through physical education classes, but schools can help increase students’ activity levels by strengthening curriculum and increasing opportunities outside these classes. - State and school district wellness policies should include stronger goals and requirements for daily physical activity. - Joint use agreements can encourage physical activity after school and on weekends, especially in low-income, inner-city, and rural areas with fewer recreational facilities. - This research synthesis summarizes evidence about different ways schools can promote physical activity. Ward, D.S. (2011). School Policies on Physical Education and Physical Activity: A Research Synthesis. Active Living Research. - Measuring the built environment can help assess needs and set priorities for creating healthy community design. - The built environment includes buildings, roads, sidewalks, utilities, homes, transit, fixtures, parks and all other man-made entities that form the physical characteristics of a community. - The BE Tool assess as core set of features selected by research experts: built environment infrastructure (e.g., road type, curb cuts/ramps, intersections/crosswalks, traffic control, transportation), walkability (e.g. sidewalk/path features, walking safety, aesthetics & amenities), bikeability (e.g., bicycle lane/path features), recreational sites and structures, and the food environment (e.g., access to grocery stores, convenience stores, farmers markets, etc.). - The built environment can influence health by affecting rates of physical activity, air pollutants such as ozone and particulate matter that can exacerbate asthma and respiratory disease, and emissions of carbon dioxide that contributes to climate change. - The manual provides background on the importance of the built environment and health and describes data collection and analysis processes for the BE Tool. The tool, instructions, and a data coding and scoring table are included. - The

ies that form the physical characteristics of a community. - The BE Tool assess as core set of features selected by research experts: built environment infrastructure (e.g., road type, curb cuts/ramps, intersections/crosswalks, traffic control, transportation), walkability (e.g. sidewalk/path features, walking safety, aesthetics & amenities), bikeability (e.g., bicycle lane/path features), recreational sites and structures, and the food environment (e.g., access to grocery stores, convenience stores, farmers markets, etc.). - The built environment can influence health by affecting rates of physical activity, air pollutants such as ozone and particulate matter that can exacerbate asthma and respiratory disease, and emissions of carbon dioxide that contributes to climate change. - The manual provides background on the importance of the built environment and health and describes data collection and analysis processes for the BE Tool. The tool, instructions, and a data coding and scoring table are included. - The BE Tool was created by ICF International through a contract with the CDC. - Kids are more active when walking and biking are safe, and Safe Routes to School programs can increase safety and active transportation to school. - Traffic speed and volume and lack of sidewalks are major barriers to active travel to school. - Active commuting can provide an estimated 16 of the 60 minutes of daily physical activity recommended for children, as found by a meta-analysis. - Implementing Safe Routes to School programs has been connected with a 44% reduction in injury rates. - This infographic summarizes highlights from the research brief “Impact of Safe Routes to School Programs on Walking and Biking” published by Active Living Research in May 2015. BEST PRACTICES AND RECOMMENDATIONS (2015) - Collaborative partnerships between schools and communities and multi-level strategies are key components of SRTS programs. - The review identified benefits, challenges and lessons learned from SRTS partnerships across studies: - Be

BE Tool was created by ICF International through a contract with the CDC. - Kids are more active when walking and biking are safe, and Safe Routes to School programs can increase safety and active transportation to school. - Traffic speed and volume and lack of sidewalks are major barriers to active travel to school. - Active commuting can provide an estimated 16 of the 60 minutes of daily physical activity recommended for children, as found by a meta-analysis. - Implementing Safe Routes to School programs has been connected with a 44% reduction in injury rates. - This infographic summarizes highlights from the research brief “Impact of Safe Routes to School Programs on Walking and Biking” published by Active Living Research in May 2015. BEST PRACTICES AND RECOMMENDATIONS (2015) - Collaborative partnerships between schools and communities and multi-level strategies are key components of SRTS programs. - The review identified benefits, challenges and lessons learned from SRTS partnerships across studies: - Benefits: “coordination of projects, programs, and policies to avoid duplication; mobilization of partners; builds lasting and trusting relationships; increases credibility and community support; partners bring unique perspectives, which increases knowledge and capacity to problem solve; builds greater sense of community; and provides opportunity for internal and external funding” - Challenges: “inexperience of volunteers; lack of time for outreach and support; difficulties to integrate programs and policies; lack of staff/volunteers; reactive responses and pushback from the community; lack of and dependence on funding support; loss of credibility; difficulties to maintain partnership; and absent stakeholders slows progress” - Lessons learned: “communication and consideration of viewpoints; partner with schools early to identify champions and establish support; implement multiple project, program and policies strategies for greater participation; expect slow progress and gradual change; target children for long

nefits: “coordination of projects, programs, and policies to avoid duplication; mobilization of partners; builds lasting and trusting relationships; increases credibility and community support; partners bring unique perspectives, which increases knowledge and capacity to problem solve; builds greater sense of community; and provides opportunity for internal and external funding” - Challenges: “inexperience of volunteers; lack of time for outreach and support; difficulties to integrate programs and policies; lack of staff/volunteers; reactive responses and pushback from the community; lack of and dependence on funding support; loss of credibility; difficulties to maintain partnership; and absent stakeholders slows progress” - Lessons learned: “communication and consideration of viewpoints; partner with schools early to identify champions and establish support; implement multiple project, program and policies strategies for greater participation; expect slow progress and gradual change; target children for long-term investment; identify key partnership leaders; have strong evaluation components to monitor progress and success; involve partners when relevant to them; build on small success and community response; and collaborate with preexisting groups, including youth groups” - Data collection methods varied across studies, and tools were often not provided, making it difficult to assess effective evaluation strategies. - This study conducted a qualitative review of 15 journal articles about Safe Routes to School programs in the U.S. and Canada. Elementary schools were more than twice as likely to have a walking school bus (WSB) if district and state policies supported safe active transportation than if no such policies were in place. - The percentage of schools nationally with WSB programs increased from 4.2% in 2008-2009 to 6.2% in 2009-2010. - Schools were 2.14 times as likely to organize a WSB program if a district policy concerning safe active transport to school was in place than if no policy existed. - Schoo

-term investment; identify key partnership leaders; have strong evaluation components to monitor progress and success; involve partners when relevant to them; build on small success and community response; and collaborate with preexisting groups, including youth groups” - Data collection methods varied across studies, and tools were often not provided, making it difficult to assess effective evaluation strategies. - This study conducted a qualitative review of 15 journal articles about Safe Routes to School programs in the U.S. and Canada. Elementary schools were more than twice as likely to have a walking school bus (WSB) if district and state policies supported safe active transportation than if no such policies were in place. - The percentage of schools nationally with WSB programs increased from 4.2% in 2008-2009 to 6.2% in 2009-2010. - Schools were 2.14 times as likely to organize a WSB program if a district policy concerning safe active transport to school was in place than if no policy existed. - Schools were 2.72 times as likely to have a WSB program if state law required school crossing guards than if no law existed. - WSB programs were more common in the Northeast (10.9% of schools) and West (7.9%) than in the South (2.9%). - Rural schools were 73% less likely to implement a WSB program than urban schools. - Schools with a majority Latino population were 78% times less likely to have a WSB than schools with a majority white population. - Data was collected through responses to a mail survey from 641 elementary schools in 2008-2009 and 680 elementary schools in 2009-2010. Turner, L., Chriqui, J.F., & Chaloupka, F.J. (2013).Walking School Bus Programs in U.S. Public Elementary Schools. Journal of Physical Activity and Health 10, 641-645. Tags: physical education; education; training; bicycle; biking; students; school; safety - The Bike Smarts skills program incorporated bike skills into elementary and middle-school physical education curriculum to address parents’ safety concerns related to biking and enc

ls were 2.72 times as likely to have a WSB program if state law required school crossing guards than if no law existed. - WSB programs were more common in the Northeast (10.9% of schools) and West (7.9%) than in the South (2.9%). - Rural schools were 73% less likely to implement a WSB program than urban schools. - Schools with a majority Latino population were 78% times less likely to have a WSB than schools with a majority white population. - Data was collected through responses to a mail survey from 641 elementary schools in 2008-2009 and 680 elementary schools in 2009-2010. Turner, L., Chriqui, J.F., & Chaloupka, F.J. (2013).Walking School Bus Programs in U.S. Public Elementary Schools. Journal of Physical Activity and Health 10, 641-645. Tags: physical education; education; training; bicycle; biking; students; school; safety - The Bike Smarts skills program incorporated bike skills into elementary and middle-school physical education curriculum to address parents’ safety concerns related to biking and encourage more students to bike to school. - The Bike Smarts program, developed by the SRTS coordinator to fit into existing physical education curriculum, consisted of four class sessions with components both in and outside the classroom. - When teaching the program, elementary and middle schools could reserve use of a trailer, bikes, and helmets purchased for shared use by the district. - Additional considerations in program development and implementation included bike maintenance, appropriate sizes of helmets, and teacher and student skill level. - A $50,000 Safe Routes to School grant from the North Carolina SRTS Program funded development of the program for Winston-Salem/Forsyth County Schools (WSFCS) in North Carolina. Wallace, J.L. & Sutton, N.P. (2015). Biked Skills Training in PE is Fun, Keeps Kids Safe. Journal of Physical Education, Recreation, & Dance. 86(2), 41-46. - Municipal officials’ involvement in local transportation policies for pedestrian and bicycle safety may be related to levels of collab

ourage more students to bike to school. - The Bike Smarts program, developed by the SRTS coordinator to fit into existing physical education curriculum, consisted of four class sessions with components both in and outside the classroom. - When teaching the program, elementary and middle schools could reserve use of a trailer, bikes, and helmets purchased for shared use by the district. - Additional considerations in program development and implementation included bike maintenance, appropriate sizes of helmets, and teacher and student skill level. - A $50,000 Safe Routes to School grant from the North Carolina SRTS Program funded development of the program for Winston-Salem/Forsyth County Schools (WSFCS) in North Carolina. Wallace, J.L. & Sutton, N.P. (2015). Biked Skills Training in PE is Fun, Keeps Kids Safe. Journal of Physical Education, Recreation, & Dance. 86(2), 41-46. - Municipal officials’ involvement in local transportation policies for pedestrian and bicycle safety may be related to levels of collaboration, perceived importance of issues, and support from the public. - Higher perceived resident support of local government to address economic development and traffic congestion through changes in the built environment was associated with increased likelihood of municipal official involvement in development, adoption, or implementation of transportation or public works policy to increase pedestrian or bicycle safety (OR= 1.70). - Perceived importance of health topics was not influential in municipal officials’ transportation policy participation. - Municipal officials who perceived lack of collaboration among departments as a barrier were less likely to be involved in transportation policy (OR = 0.78). - Municipal officials who lived in the city or town where they worked were more likely to be involved in transportation policy (OR=1.83). - This online cross-sectional survey gathered responses from 461 municipal officials from public health, planning, transportation, public works, community and economic dev

oration, perceived importance of issues, and support from the public. - Higher perceived resident support of local government to address economic development and traffic congestion through changes in the built environment was associated with increased likelihood of municipal official involvement in development, adoption, or implementation of transportation or public works policy to increase pedestrian or bicycle safety (OR= 1.70). - Perceived importance of health topics was not influential in municipal officials’ transportation policy participation. - Municipal officials who perceived lack of collaboration among departments as a barrier were less likely to be involved in transportation policy (OR = 0.78). - Municipal officials who lived in the city or town where they worked were more likely to be involved in transportation policy (OR=1.83). - This online cross-sectional survey gathered responses from 461 municipal officials from public health, planning, transportation, public works, community and economic development, parks and recreation, city management, and municipal legislatures in 83 urban areas across 8 states in 2012. Zwald, M., Eyler, A., Goins, K., Brownson, R., Schmid, T., & Lemon, S. (2014). Understanding Municipal Officials' Involvement in Transportation Policies Supportive of Walking and Bicycling. Journal of Public Health Management & Practice. 0(0), 1-8. - There is promising evidence that walking school buses (WSBs) can impact children’s health and safety skills, and supporting facilitators and eliminating barriers to WSBs could improve program sustainability. - Three studies demonstrated a positive relationship between WSBs and proportions of children walking to school through self-report, and three studies showed an association between WSBs and increased activity levels using accelerometers, although not always at statistically significant levels. - Two studies reported savings in car journeys as a result of WSBs. - One study found that WSB schools had a five-fold improvement in children crossing

elopment, parks and recreation, city management, and municipal legislatures in 83 urban areas across 8 states in 2012. Zwald, M., Eyler, A., Goins, K., Brownson, R., Schmid, T., & Lemon, S. (2014). Understanding Municipal Officials' Involvement in Transportation Policies Supportive of Walking and Bicycling. Journal of Public Health Management & Practice. 0(0), 1-8. - There is promising evidence that walking school buses (WSBs) can impact children’s health and safety skills, and supporting facilitators and eliminating barriers to WSBs could improve program sustainability. - Three studies demonstrated a positive relationship between WSBs and proportions of children walking to school through self-report, and three studies showed an association between WSBs and increased activity levels using accelerometers, although not always at statistically significant levels. - Two studies reported savings in car journeys as a result of WSBs. - One study found that WSB schools had a five-fold improvement in children crossing at intersections instead of non-intersection locations. - Child and parent enjoyment during participation, parents’ time savings, and effective information provision and promotion were key facilitators of WSBs. - Parent road safety concerns were the most common barrier across the literature, cited in 10 of 12 studies. - Recruitment of volunteers and children to participate was also a common challenge, and time commitment from coordinators, variable family travel schedules, and lower motivation in winter months can affect recruitment. - This systematic review examined 12 studies conducted between 2001 and 2012 that focused solely on WSBs. These studies included 326 schools in a variety of socio-demographic contexts in Australia, New Zealand, and the United States. - Studies generally focused on either the impact of WSBs on child activity, health, and safety, or barriers and facilitators to implementation. Smith, L, Norgate, SH, Cherrett, T, Davies, N, Wistanley, C and Harding, M. (2015.) Walking school buses

at intersections instead of non-intersection locations. - Child and parent enjoyment during participation, parents’ time savings, and effective information provision and promotion were key facilitators of WSBs. - Parent road safety concerns were the most common barrier across the literature, cited in 10 of 12 studies. - Recruitment of volunteers and children to participate was also a common challenge, and time commitment from coordinators, variable family travel schedules, and lower motivation in winter months can affect recruitment. - This systematic review examined 12 studies conducted between 2001 and 2012 that focused solely on WSBs. These studies included 326 schools in a variety of socio-demographic contexts in Australia, New Zealand, and the United States. - Studies generally focused on either the impact of WSBs on child activity, health, and safety, or barriers and facilitators to implementation. Smith, L, Norgate, SH, Cherrett, T, Davies, N, Wistanley, C and Harding, M. (2015.) Walking school buses as a form of active transportation for children: A review of the evidence. Journal of School Health. 85, 197-210. - Biking and walking to school may vary by factors like distance to school, speed of traffic, school encouragement, and children asking permission. - Students were 2.6 times as likely to walk or bike to school if these modes were promoted by the school. - Students who lived within 0.5 miles of the school were 16.7 times as likely to walk or bike to school than those living further away. - Lower travel times were associated with higher percentages of walking and biking to school; 23.8% of children biked or walked who were less than 5 minutes away, while only 2.2% of children more than 20 minutes utilized active modes. - More children in kindergarten through fifth grade walked or biked to school than children in sixth through eighth grade. - Students who asked permission from their parents to walk or bike to school in the past year were seven times as likely to be using active transportation modes.

as a form of active transportation for children: A review of the evidence. Journal of School Health. 85, 197-210. - Biking and walking to school may vary by factors like distance to school, speed of traffic, school encouragement, and children asking permission. - Students were 2.6 times as likely to walk or bike to school if these modes were promoted by the school. - Students who lived within 0.5 miles of the school were 16.7 times as likely to walk or bike to school than those living further away. - Lower travel times were associated with higher percentages of walking and biking to school; 23.8% of children biked or walked who were less than 5 minutes away, while only 2.2% of children more than 20 minutes utilized active modes. - More children in kindergarten through fifth grade walked or biked to school than children in sixth through eighth grade. - Students who asked permission from their parents to walk or bike to school in the past year were seven times as likely to be using active transportation modes. - Children whose parents reported recognizing most people on the block were 1.6 times as likely to walk or bike to school compared to children whose parents did not recognize most people. - · Children of parents who reported speed of traffic as a significant factor affecting their decision to allow children to walk/bike to school were 58% less likely to walk/bike to school than parents who did not identify speed as a significant factor. - This study conducted a baseline assessment of 5 SRTS-awarded schools from pre-kindergarten to eighth grade in communities with similar median incomes in Louisiana. Data was collected using parent surveys, teacher tallies, and the Pedestrian Environmental Data Scan (PEDS). Gustat, J., Richards, K., Rice, J., Andersen, L., Parker-Karst, K., Cole, S. (2015). Youth Walking and Biking Rates Vary by Environments Around 5 Louisiana Schools. Journal of School Health, 85 (1), 36-42. - National governments have provided subsidies for investments in increasing the safety and attractive

- Children whose parents reported recognizing most people on the block were 1.6 times as likely to walk or bike to school compared to children whose parents did not recognize most people. - · Children of parents who reported speed of traffic as a significant factor affecting their decision to allow children to walk/bike to school were 58% less likely to walk/bike to school than parents who did not identify speed as a significant factor. - This study conducted a baseline assessment of 5 SRTS-awarded schools from pre-kindergarten to eighth grade in communities with similar median incomes in Louisiana. Data was collected using parent surveys, teacher tallies, and the Pedestrian Environmental Data Scan (PEDS). Gustat, J., Richards, K., Rice, J., Andersen, L., Parker-Karst, K., Cole, S. (2015). Youth Walking and Biking Rates Vary by Environments Around 5 Louisiana Schools. Journal of School Health, 85 (1), 36-42. - National governments have provided subsidies for investments in increasing the safety and attractiveness of walking and biking to school. Evaluations of Safe Routes to School initiatives have found that they have been effective at changing behavior and reducing injuries. - However, there has been little attention to the impacts of these programs on pupil transportation costs. - This analysis assesses the potential economic benefits of Safe Routes to School programs in the US context by estimating the annual costs of using motorized transport for short trips to schools, examining real-world examples of the costs savings of SRTS programs, and evaluating land use impacts on school transportation costs using a simulation analysis of school bus routes. - We find that there is potential for school districts and families to reduce transport expenditures through public sector investments in walking and biking infrastructure near schools. We also find that land use context matters and the most cost-effective investments would benefit schools where large numbers of children live within walking distance. McDonald NC,

ness of walking and biking to school. Evaluations of Safe Routes to School initiatives have found that they have been effective at changing behavior and reducing injuries. - However, there has been little attention to the impacts of these programs on pupil transportation costs. - This analysis assesses the potential economic benefits of Safe Routes to School programs in the US context by estimating the annual costs of using motorized transport for short trips to schools, examining real-world examples of the costs savings of SRTS programs, and evaluating land use impacts on school transportation costs using a simulation analysis of school bus routes. - We find that there is potential for school districts and families to reduce transport expenditures through public sector investments in walking and biking infrastructure near schools. We also find that land use context matters and the most cost-effective investments would benefit schools where large numbers of children live within walking distance. McDonald NC, Steiner RL, Palmer WM, Bullock AN, Sisiopiku VP, and Lytle BF. Costs of school transportation: quantifying the fiscal impacts of encouraging walking and bicycling for school travel. Transportation 2014, November. - Objective. Joint use policies (JUP) encourage shared facility use, usually between schools and a city or private organization, for both physical activity-related and non-physical activity-related programs. Little is known about JUP's impact on physical activity (PA). This study examined whether more specific JUPs were associated with increased PA and decreased sedentary behavior (SB) in adolescents. - Methods. Data on PA, sports participation, and SB were taken from annual cross-sectional nationally representative samples of 51,269 8th, 10th and 12th grade public school students nested in 461 school districts in the US from 2009–2011. JUP measures were constructed using information obtained from corresponding school district JU policies. Multivariable analyses were conducted, controlling for indivi

Steiner RL, Palmer WM, Bullock AN, Sisiopiku VP, and Lytle BF. Costs of school transportation: quantifying the fiscal impacts of encouraging walking and bicycling for school travel. Transportation 2014, November. - Objective. Joint use policies (JUP) encourage shared facility use, usually between schools and a city or private organization, for both physical activity-related and non-physical activity-related programs. Little is known about JUP's impact on physical activity (PA). This study examined whether more specific JUPs were associated with increased PA and decreased sedentary behavior (SB) in adolescents. - Methods. Data on PA, sports participation, and SB were taken from annual cross-sectional nationally representative samples of 51,269 8th, 10th and 12th grade public school students nested in 461 school districts in the US from 2009–2011. JUP measures were constructed using information obtained from corresponding school district JU policies. Multivariable analyses were conducted, controlling for individual demographic and socioeconomic characteristics and clustering at the district level. - Results. Results showed small associations between more specific JUPs and increased PA (IRR 1.01, 95% CI: 1.00, 1.02). Closer examination of specific JUP provisions indicates that specifying what times facilities are available for use was associated with vigorous exercise and prioritizing school or affiliated organizations' use and which spaces were available for use were associated with vigorous exercise and more frequent PA participation, which includes participation in sports or athletics. No associations were found between more specific JUPs and SB. - Conclusions. JUPS may have small influences on adolescent physical activity behavior. Future longitudinal studies should be conducted to examine the impact of JUPs in conjunction with other physical activity-related policies and environmental changes to determine what impact they have on overall adolescent physical activity and sedentary behavior. Slater S, Chriqui J,

dual demographic and socioeconomic characteristics and clustering at the district level. - Results. Results showed small associations between more specific JUPs and increased PA (IRR 1.01, 95% CI: 1.00, 1.02). Closer examination of specific JUP provisions indicates that specifying what times facilities are available for use was associated with vigorous exercise and prioritizing school or affiliated organizations' use and which spaces were available for use were associated with vigorous exercise and more frequent PA participation, which includes participation in sports or athletics. No associations were found between more specific JUPs and SB. - Conclusions. JUPS may have small influences on adolescent physical activity behavior. Future longitudinal studies should be conducted to examine the impact of JUPs in conjunction with other physical activity-related policies and environmental changes to determine what impact they have on overall adolescent physical activity and sedentary behavior. Slater S, Chriqui J, Chaloupka FJ, Johnston L. Joint use policies: Are they related to adolescent behavior? Prev. Med 2014 Dec; 69S:S37-S43. - Defining healthy schools remains largely discipline specific. Design disciplines ground discussions in a “green building” framework. Public health approaches healthy schools through programmatic interventions for physical activity and nutrition. - This article presents a more systemic approach to healthy schools via health impact assessment (HIA). It reviews literature on health determinants in school environments, focusing on physical design. Existing school HIAs are reviewed with other decision support tools that provide guidance on the operation and design of healthy schools. - The paper examines current use of HIAs in schools and develops a screening matrix for using HIA in creating healthy schools. Arthi Rao, Catherine L. Ross. Health Impact Assessments and Healthy Schools. Journal of Planning Education and Research 2014;34(2):141-152. - Despite the growing interest in expanding the j

Chaloupka FJ, Johnston L. Joint use policies: Are they related to adolescent behavior? Prev. Med 2014 Dec; 69S:S37-S43. - Defining healthy schools remains largely discipline specific. Design disciplines ground discussions in a “green building” framework. Public health approaches healthy schools through programmatic interventions for physical activity and nutrition. - This article presents a more systemic approach to healthy schools via health impact assessment (HIA). It reviews literature on health determinants in school environments, focusing on physical design. Existing school HIAs are reviewed with other decision support tools that provide guidance on the operation and design of healthy schools. - The paper examines current use of HIAs in schools and develops a screening matrix for using HIA in creating healthy schools. Arthi Rao, Catherine L. Ross. Health Impact Assessments and Healthy Schools. Journal of Planning Education and Research 2014;34(2):141-152. - Despite the growing interest in expanding the joint use of K–12 public schools by public health and planning practitioners to promote healthy, sustainable communities, the topic has received little attention in the urban planning and public health scholarship. - The objective of this article is to situate joint use in the academic literature focused on the links between built environments and health. - The author examines the “state of the field” of K–12 joint use through studying the academic and associated literature, interviews, participant observation, and case examples and develops a joint use classification system to aid researchers and practitioners. Vincent J. Joint Use of Public Schools: A Framework for Promoting Healthy Communities. Journal of Planning Education and Research 2014;34(2):153-168. - In 2005, the United States Congress directed the Federal Highway Administration (FHWA) to develop the Nonmotorized Transportation Pilot Program (NTPP). - The program provided over $25 million in contract authority to four pilot communities (Columbia, Mi

oint use of K–12 public schools by public health and planning practitioners to promote healthy, sustainable communities, the topic has received little attention in the urban planning and public health scholarship. - The objective of this article is to situate joint use in the academic literature focused on the links between built environments and health. - The author examines the “state of the field” of K–12 joint use through studying the academic and associated literature, interviews, participant observation, and case examples and develops a joint use classification system to aid researchers and practitioners. Vincent J. Joint Use of Public Schools: A Framework for Promoting Healthy Communities. Journal of Planning Education and Research 2014;34(2):153-168. - In 2005, the United States Congress directed the Federal Highway Administration (FHWA) to develop the Nonmotorized Transportation Pilot Program (NTPP). - The program provided over $25 million in contract authority to four pilot communities (Columbia, Missouri; Marin County, California; Minneapolis area, Minnesota; and Sheboygan County, Wisconsin) for pedestrian and bicycle infrastructure and nonmotorized programs. - This report summarizes the progress and results of the NTPP from August 2005 through December 2013, updating and expanding upon the analysis from the Report to the U.S. Congress on the Outcomes of the Nonmotorized Transportation Pilot Program, submitted by the Federal Highway Administration in April 2012. - This report analyzes the results through December 2013 of the NTPP in terms of program implementation, transportation mode shift toward walking and bicycling and associated improvements pertaining to access and mobility, safety and public health, and the environment and energy. - From 2007 to 2013, the pilot communities observed an estimated 22.8 percent increase in the number of walking trips and an estimated 48.3 percent increase in the number of bicycling trips. - This report examines how the NTPP pilot communities provide examples to othe

ssouri; Marin County, California; Minneapolis area, Minnesota; and Sheboygan County, Wisconsin) for pedestrian and bicycle infrastructure and nonmotorized programs. - This report summarizes the progress and results of the NTPP from August 2005 through December 2013, updating and expanding upon the analysis from the Report to the U.S. Congress on the Outcomes of the Nonmotorized Transportation Pilot Program, submitted by the Federal Highway Administration in April 2012. - This report analyzes the results through December 2013 of the NTPP in terms of program implementation, transportation mode shift toward walking and bicycling and associated improvements pertaining to access and mobility, safety and public health, and the environment and energy. - From 2007 to 2013, the pilot communities observed an estimated 22.8 percent increase in the number of walking trips and an estimated 48.3 percent increase in the number of bicycling trips. - This report examines how the NTPP pilot communities provide examples to other communities interested in implementing and evaluating nonmotorized investments. William Lyons, Benjamin Rasmussen, David Daddio, Jared Fijalkowski, Erica Simmons. (2014). Nonmotorized Transportation Pilot Program: Continued Progress in Developing Walking and Bicycling Networks – May 2014 Report In U. S. D. o. Transportation, J. A. V. N. T. S. Center & T. P. Division (Eds.). 55 Broadway Cambridge, MA 02142-1093: US Dept of Transportation. - Purpose and Method: This research brief examines elementary school administrators’ reports of school participation in Safe Routes to School initiatives and estimated rates of active travel by students, as collected by surveys from administrators at nationally-representative samples of U.S. public elementary schools between the 2006-07 and 2012-13 school years. - Results: The prevalence of elementary school participation in SRTS programs grew steadily over the past seven years, increasing by 54 percent between 2006-07 and 2012-13 (from14.2% of schools to 21.8% of schools).

r communities interested in implementing and evaluating nonmotorized investments. William Lyons, Benjamin Rasmussen, David Daddio, Jared Fijalkowski, Erica Simmons. (2014). Nonmotorized Transportation Pilot Program: Continued Progress in Developing Walking and Bicycling Networks – May 2014 Report In U. S. D. o. Transportation, J. A. V. N. T. S. Center & T. P. Division (Eds.). 55 Broadway Cambridge, MA 02142-1093: US Dept of Transportation. - Purpose and Method: This research brief examines elementary school administrators’ reports of school participation in Safe Routes to School initiatives and estimated rates of active travel by students, as collected by surveys from administrators at nationally-representative samples of U.S. public elementary schools between the 2006-07 and 2012-13 school years. - Results: The prevalence of elementary school participation in SRTS programs grew steadily over the past seven years, increasing by 54 percent between 2006-07 and 2012-13 (from14.2% of schools to 21.8% of schools). Rates of student active travel to school, as estimated by school administrators, were 60 percent higher at schools that participated in SRTS programs (where 32.4% of students walked or biked) than at schools that did not participate (where 20.2% of students walked or biked). In examining the 2012-13 survey, SRTS programming did not differ by the school’s socioeconomic characteristics. - Conclusions: Active travel is a promising strategy for keeping children physically active and for reducing the adverse health consequences of inactivity, such as childhood obesity. SRTS programs are associated with higher reported rates of children walking or biking to school. Turner L, Slater S, Chaloupka FJ. . (2014). Elementary School Participation in Safe Routes to School Programming is Associated with Higher Rates of Student Active Travel to School. In H. P. C. Bridging the Gap Program, Institute for Health Research and Policy (Ed.), A BTG Research Brief. Chicago, IL.: University of Illinois at Chicago. - Purpose: State

Rates of student active travel to school, as estimated by school administrators, were 60 percent higher at schools that participated in SRTS programs (where 32.4% of students walked or biked) than at schools that did not participate (where 20.2% of students walked or biked). In examining the 2012-13 survey, SRTS programming did not differ by the school’s socioeconomic characteristics. - Conclusions: Active travel is a promising strategy for keeping children physically active and for reducing the adverse health consequences of inactivity, such as childhood obesity. SRTS programs are associated with higher reported rates of children walking or biking to school. Turner L, Slater S, Chaloupka FJ. . (2014). Elementary School Participation in Safe Routes to School Programming is Associated with Higher Rates of Student Active Travel to School. In H. P. C. Bridging the Gap Program, Institute for Health Research and Policy (Ed.), A BTG Research Brief. Chicago, IL.: University of Illinois at Chicago. - Purpose: State Safe Routes to School (SRTS) programs provide competitive grants to local projects that support safe walking, bicycling, and other modes of active school travel (AST). This study assessed changes in rates of AST after implementation of SRTS projects at multiple sites across four states (Florida, Mississippi, Washington and Wisconsin). - Measures: AST was measured as the percentage of students walking, bicycling, or using any AST mode. SRTS project characteristics were measured at the project, school, and school neighborhood levels in 53 schools affected by 48 completed Safe Routes to School projects. - Results: Statistically significant increases in AST were observed across projects in all four states. All AST modes increased from 12.9% to 17.6%; walking from 9.8% to 14.2%; and bicycling from 2.5% to 3.0%. Increases in rates of bicycling were negatively correlated with baseline rates of bicycling. - Conclusion: State-funded SRTS projects are achieving one of the primary program goals of increasing rates of AS

Safe Routes to School (SRTS) programs provide competitive grants to local projects that support safe walking, bicycling, and other modes of active school travel (AST). This study assessed changes in rates of AST after implementation of SRTS projects at multiple sites across four states (Florida, Mississippi, Washington and Wisconsin). - Measures: AST was measured as the percentage of students walking, bicycling, or using any AST mode. SRTS project characteristics were measured at the project, school, and school neighborhood levels in 53 schools affected by 48 completed Safe Routes to School projects. - Results: Statistically significant increases in AST were observed across projects in all four states. All AST modes increased from 12.9% to 17.6%; walking from 9.8% to 14.2%; and bicycling from 2.5% to 3.0%. Increases in rates of bicycling were negatively correlated with baseline rates of bicycling. - Conclusion: State-funded SRTS projects are achieving one of the primary program goals of increasing rates of AST. They may be particularly effective at introducing bicycling to communities where it is rare. The evaluation framework introduced in this study can be used to continue tracking the effect of state SRTS programs as more projects are completed. Orion Stewart, Anne Vernez Moudon, and Charlotte Claybrooke (2014). Multistate Evaluation of Safe Routes to School Programs. American Journal of Health Promotion, 28(sp3), S89-S96. - Objective. We evaluated the cost-effectiveness of a package of roadway modifications in New York City funded under the Safe Routes to School (SRTS) program. - Methods. We used a Markov model to estimate long-term impacts of SRTS on injury reduction and the associated savings in medical costs, lifelong disability, and death. Model inputs included societal costs (in 2013 US dollars) and observed spatiotemporal changes in injury rates associated with New York City's implementation of SRTS relative to control intersections. Structural changes to roadways were assumed to last 50 years before fu

T. They may be particularly effective at introducing bicycling to communities where it is rare. The evaluation framework introduced in this study can be used to continue tracking the effect of state SRTS programs as more projects are completed. Orion Stewart, Anne Vernez Moudon, and Charlotte Claybrooke (2014). Multistate Evaluation of Safe Routes to School Programs. American Journal of Health Promotion, 28(sp3), S89-S96. - Objective. We evaluated the cost-effectiveness of a package of roadway modifications in New York City funded under the Safe Routes to School (SRTS) program. - Methods. We used a Markov model to estimate long-term impacts of SRTS on injury reduction and the associated savings in medical costs, lifelong disability, and death. Model inputs included societal costs (in 2013 US dollars) and observed spatiotemporal changes in injury rates associated with New York City's implementation of SRTS relative to control intersections. Structural changes to roadways were assumed to last 50 years before further investment is required. Therefore, costs were discounted over 50 consecutive cohorts of modified roadway users under SRTS. - Results. SRTS was associated with an overall net societal benefit of $230 million and 2055 quality-adjusted life years gained in New York City. - Conclusions. SRTS reduces injuries and saves money over the long run. Muennig, P. A., Epstein, M., Li, G., & DiMaggio, C. (2014). The Cost-Effectiveness of New York City's Safe Routes to School Program. Am J Public Health. doi: 10.2105/ajph.2014.301868 - Despite the health benefits associated with physical activity participation, activity levels of North American children are declining. In response, practitioners are placing emphasis on active forms of transportation to and from school. The purpose of this study was to explore the barriers and facilitators to active transportation to school (ATS) from the perspectives of practitioners. - The perspectives of 19 practitioners (eg, health promoters, traffic engineers, police, etc.) from 3 c

rther investment is required. Therefore, costs were discounted over 50 consecutive cohorts of modified roadway users under SRTS. - Results. SRTS was associated with an overall net societal benefit of $230 million and 2055 quality-adjusted life years gained in New York City. - Conclusions. SRTS reduces injuries and saves money over the long run. Muennig, P. A., Epstein, M., Li, G., & DiMaggio, C. (2014). The Cost-Effectiveness of New York City's Safe Routes to School Program. Am J Public Health. doi: 10.2105/ajph.2014.301868 - Despite the health benefits associated with physical activity participation, activity levels of North American children are declining. In response, practitioners are placing emphasis on active forms of transportation to and from school. The purpose of this study was to explore the barriers and facilitators to active transportation to school (ATS) from the perspectives of practitioners. - The perspectives of 19 practitioners (eg, health promoters, traffic engineers, police, etc.) from 3 communities in Alberta, Canada were captured using focus group interviews followed by content analysis. - Subthemes tied to barriers included logistics, lifestyle, safety, and lack of resources; while facilitators were comprised of collaboration, education, and leadership. The results were interpreted using an ecological model of health behavior. - The most common ATS barriers: attitudes and safety concerns, lack of resources and time, and the nature of the natural and built environments were associated with the intrapersonal, organizational, and physical environmental factors, respectively. The most significant organizational facilitators concerned collaboration among parents, schools, businesses, community organizations, and government agencies. While the multifaceted nature of barriers and facilitators add complexity to the issue, it also challenges practitioners to think and act creatively in finding solutions. Loitz CC, Spencer-Cavaliere N. (2013). Exploring the Barriers and Facilitators to Children's Act

ommunities in Alberta, Canada were captured using focus group interviews followed by content analysis. - Subthemes tied to barriers included logistics, lifestyle, safety, and lack of resources; while facilitators were comprised of collaboration, education, and leadership. The results were interpreted using an ecological model of health behavior. - The most common ATS barriers: attitudes and safety concerns, lack of resources and time, and the nature of the natural and built environments were associated with the intrapersonal, organizational, and physical environmental factors, respectively. The most significant organizational facilitators concerned collaboration among parents, schools, businesses, community organizations, and government agencies. While the multifaceted nature of barriers and facilitators add complexity to the issue, it also challenges practitioners to think and act creatively in finding solutions. Loitz CC, Spencer-Cavaliere N. (2013). Exploring the Barriers and Facilitators to Children's Active Transportation to and From School From the Perspectives of Practitioners. J Phys Act Health, 10(8), 1128-1135. - In many developed countries walking and bicycling are not extensively used as a means of transportation. Further, the share of these non-motorized travel modes (as a percentage of all trips) has been reducing over time. - The increasingly low use of walk and bicycle modes of transportation, and the concomitant increasing use of motorized vehicles for transportation, may be associated with several factors, including land use and development patterns, traffic safety and personal security concerns, and perceptions of and attitudes towards non-motorized transport. These factors manifest themselves differently in developing and developed countries, but throughout the world the increasing reliance on motorized transport contributes to serious traffic congestion problems, air quality degradation, and greenhouse gas emission increases. - In addition to transportation professionals, health agencies are

ive Transportation to and From School From the Perspectives of Practitioners. J Phys Act Health, 10(8), 1128-1135. - In many developed countries walking and bicycling are not extensively used as a means of transportation. Further, the share of these non-motorized travel modes (as a percentage of all trips) has been reducing over time. - The increasingly low use of walk and bicycle modes of transportation, and the concomitant increasing use of motorized vehicles for transportation, may be associated with several factors, including land use and development patterns, traffic safety and personal security concerns, and perceptions of and attitudes towards non-motorized transport. These factors manifest themselves differently in developing and developed countries, but throughout the world the increasing reliance on motorized transport contributes to serious traffic congestion problems, air quality degradation, and greenhouse gas emission increases. - In addition to transportation professionals, health agencies are also paying increased attention to non-motorized modes, or “active transport” as a route to improve public health. - In this chapter, the authors discuss the many benefits of non-motorized travel, identify its facilitators and impediments, analyze its utilization in select developed and developing countries, review previous studies of the effectiveness of strategies to promote it, and recommend possible pathways to promote non-motorized travel as a sustainable travel option. Christina Bernardo, Chandra Bhat. (2014). Non-motorized Travel as a Sustainable Travel Option Handbook of Sustainable Travel (pp. 277-291). Netherlands: Springer Netherlands. - This study assesses how federal Safe Routes to School (SRTS) funds were allocated to public and private schools and communities and whether there were demographic or locational differences between schools that benefited from SRTS funding and those that did not receive SRTS awards. - The study analyzes all SRTS projects awarded between 2005 and 2012 (N1⁄45532) by us

also paying increased attention to non-motorized modes, or “active transport” as a route to improve public health. - In this chapter, the authors discuss the many benefits of non-motorized travel, identify its facilitators and impediments, analyze its utilization in select developed and developing countries, review previous studies of the effectiveness of strategies to promote it, and recommend possible pathways to promote non-motorized travel as a sustainable travel option. Christina Bernardo, Chandra Bhat. (2014). Non-motorized Travel as a Sustainable Travel Option Handbook of Sustainable Travel (pp. 277-291). Netherlands: Springer Netherlands. - This study assesses how federal Safe Routes to School (SRTS) funds were allocated to public and private schools and communities and whether there were demographic or locational differences between schools that benefited from SRTS funding and those that did not receive SRTS awards. - The study analyzes all SRTS projects awarded between 2005 and 2012 (N1⁄45532) by using descriptive statistics to profile SRTS funding amounts and purposes, and to compare demographic and neighborhood characteristics of schools with and without SRTS programs. Analysis was conducted in 2013. - The average SRTS award was $158,930 and most funding was spent on infrastructure (62.8%) or combined infrastructure and non-infrastructure (23.5%) projects. - Schools benefiting from the SRTS program served higher proportions of Latino students and were more likely to be in higher-density areas. Few differences existed in neighborhood demographics, particularly educational attainment, work-trip commute mode, and median household income. - Conclusions: Schools benefiting from the SRTS program are more urban and have higher Latino populations but are otherwise comparable to U.S. public schools. This suggests that disadvantaged areas have had access to the SRTS program. Noreen C. McDonald, PhD, Pamela H. Barth, MRP, Ruth L. Steiner, PhD. (2013). Assessing the Distribution of Safe Routes to School Program F

ing descriptive statistics to profile SRTS funding amounts and purposes, and to compare demographic and neighborhood characteristics of schools with and without SRTS programs. Analysis was conducted in 2013. - The average SRTS award was $158,930 and most funding was spent on infrastructure (62.8%) or combined infrastructure and non-infrastructure (23.5%) projects. - Schools benefiting from the SRTS program served higher proportions of Latino students and were more likely to be in higher-density areas. Few differences existed in neighborhood demographics, particularly educational attainment, work-trip commute mode, and median household income. - Conclusions: Schools benefiting from the SRTS program are more urban and have higher Latino populations but are otherwise comparable to U.S. public schools. This suggests that disadvantaged areas have had access to the SRTS program. Noreen C. McDonald, PhD, Pamela H. Barth, MRP, Ruth L. Steiner, PhD. (2013). Assessing the Distribution of Safe Routes to School Program Funds, 2005–2012. Am J Prev Med, 45(4), 401-406 - The study used a robust quasi-experimental research design to measure the impacts of Eugene, Oregon's Safe Routes to School program on walking and biking. - Using data collected between 2007 and 2011 at 14 schools with and without Safe Routes to School programs, the study showed that the Safe Routes to School program was associated with increases in walking and biking. - Education and encouragement programs were associated with a five percentage point increase in biking. Augmenting education programs with additional SRTS improvements such as sidewalks, crosswalks, covered bike parking, and Boltage was associated with increases in walking and biking of 5–20 percentage points. - The study results illustrate the potential for the Safe Routes to School program to change behavior and should encourage other communities to plan for multi-modal school travel. Noreen C. McDonald a, n, Yizhao Yang b, Steve M. Abbott b, Allison N. Bullock (2013). Impact of the Safe Routes

unds, 2005–2012. Am J Prev Med, 45(4), 401-406 - The study used a robust quasi-experimental research design to measure the impacts of Eugene, Oregon's Safe Routes to School program on walking and biking. - Using data collected between 2007 and 2011 at 14 schools with and without Safe Routes to School programs, the study showed that the Safe Routes to School program was associated with increases in walking and biking. - Education and encouragement programs were associated with a five percentage point increase in biking. Augmenting education programs with additional SRTS improvements such as sidewalks, crosswalks, covered bike parking, and Boltage was associated with increases in walking and biking of 5–20 percentage points. - The study results illustrate the potential for the Safe Routes to School program to change behavior and should encourage other communities to plan for multi-modal school travel. Noreen C. McDonald a, n, Yizhao Yang b, Steve M. Abbott b, Allison N. Bullock (2013). Impact of the Safe Routes to School program on walking and biking: Eugene, Oregon study. Transport Policy 29 (2013) 243–248, 29, 243-248 - Household and parental characteristics and perceptions of walking and the built environment may reduce the propensity of children to use active travel modes (walking and bicycling) for their school trip. - This paper examines whether there is a relationship between walking or bicycling to school and the walking habits of caregivers or parents. - A statewide pedestrian survey of New Jersey residents was used to assess the mode taken by children for their school trip (age of respondents (parents) 19–84; n=353). Socio-demographic characteristics, public school density, full and part-time employment status of respondents, self-reported frequency of walking of adult respondents and perceived neighborhood environment characteristics are used as independent variables. Logit models are estimated to test associations between these variables. - Non-minority ethnic status, women respondent's employment type,

to School program on walking and biking: Eugene, Oregon study. Transport Policy 29 (2013) 243–248, 29, 243-248 - Household and parental characteristics and perceptions of walking and the built environment may reduce the propensity of children to use active travel modes (walking and bicycling) for their school trip. - This paper examines whether there is a relationship between walking or bicycling to school and the walking habits of caregivers or parents. - A statewide pedestrian survey of New Jersey residents was used to assess the mode taken by children for their school trip (age of respondents (parents) 19–84; n=353). Socio-demographic characteristics, public school density, full and part-time employment status of respondents, self-reported frequency of walking of adult respondents and perceived neighborhood environment characteristics are used as independent variables. Logit models are estimated to test associations between these variables. - Non-minority ethnic status, women respondent's employment type, higher income, and vehicle ownership are negatively associated with active travel to school, while higher public school density is positively associated with choice of an active travel mode. - Even in favorable circumstances for active travel to school, the employment circumstances of parents or caregivers may deter children from walking to school. - When parents are active, their children are also more likely to be active. Poor sidewalk quality also deters parents from letting children use active modes for their school trip. Hyunsoo Parka, Robert B. Nolanda. (2013). Active school trips: associations with caregiver walking frequency. Transport Policy, 29, 23-38 - Few reports examined long term predictors of children's active commuting to school (walking or cycling to school, ACS). - To identify predictors of ACS over one school year among a sample of children with relatively high rates of ACS. - Parents were surveyed in September 2010 (Time 1) and April 2011 (Time 2). The dependent variable was children's co

higher income, and vehicle ownership are negatively associated with active travel to school, while higher public school density is positively associated with choice of an active travel mode. - Even in favorable circumstances for active travel to school, the employment circumstances of parents or caregivers may deter children from walking to school. - When parents are active, their children are also more likely to be active. Poor sidewalk quality also deters parents from letting children use active modes for their school trip. Hyunsoo Parka, Robert B. Nolanda. (2013). Active school trips: associations with caregiver walking frequency. Transport Policy, 29, 23-38 - Few reports examined long term predictors of children's active commuting to school (walking or cycling to school, ACS). - To identify predictors of ACS over one school year among a sample of children with relatively high rates of ACS. - Parents were surveyed in September 2010 (Time 1) and April 2011 (Time 2). The dependent variable was children's commuting mode to school (active versus passive). Independent variables included: 1) parents' outcome expectations (from Social Cognitive Theory: the expected risks/benefits for their child doing ACS), 2) distance to school, 3) participation in an adult-led walk to school group, 4) temperature, and 5) child demographics. Generalized mixed-models estimated odds ratios for ACS (n=369 or 49.7% of Time 1 respondents). - ACS was associated with the following: - males (OR=2.59, 95% CI [1.57-4.30]) - adult-led walk to school group participation (OR=1.80, 95% CI [1.14-2.86]) - parents' outcome expectations (OR=1.26, 95% CI [1.14-1.39]) - temperature (OR=1.03, 95% CI [1.01-1.07) - distance to school (OR=0.23, 95% CI [0.14-0.37]) - Latino ethnicity (OR=0.28, 95% CI [0.12-0.65]). - CONCLUSIONS: Programs and policies sensitive to parents' concerns, e.g. adult-led walk to school groups, and targeting Latinos and girls appear promising for increasing ACS. Mendoza JA, Cowan D, Liu Y. (2013). Predictors of Children's Active Co

mmuting mode to school (active versus passive). Independent variables included: 1) parents' outcome expectations (from Social Cognitive Theory: the expected risks/benefits for their child doing ACS), 2) distance to school, 3) participation in an adult-led walk to school group, 4) temperature, and 5) child demographics. Generalized mixed-models estimated odds ratios for ACS (n=369 or 49.7% of Time 1 respondents). - ACS was associated with the following: - males (OR=2.59, 95% CI [1.57-4.30]) - adult-led walk to school group participation (OR=1.80, 95% CI [1.14-2.86]) - parents' outcome expectations (OR=1.26, 95% CI [1.14-1.39]) - temperature (OR=1.03, 95% CI [1.01-1.07) - distance to school (OR=0.23, 95% CI [0.14-0.37]) - Latino ethnicity (OR=0.28, 95% CI [0.12-0.65]). - CONCLUSIONS: Programs and policies sensitive to parents' concerns, e.g. adult-led walk to school groups, and targeting Latinos and girls appear promising for increasing ACS. Mendoza JA, Cowan D, Liu Y. (2013). Predictors of Children's Active Commuting to School: An Observational Evaluation in Five US Communities. J Phys Act Health. Epublished. - We assessed changes in transit-associated walking in the United States from 2001 to 2009 and documented their importance to public health. - We examined transit walk times using the National Household Travel Survey, a telephone survey administered by the US Department of Transportation to examine travel behavior in the United States. - People are more likely to transit walk if they are from lower income households, are non-White, and live in large urban areas with access to rail systems. Transit walkers in large urban areas with a rail system were 72% more likely to transit walk 30 minutes or more per day than were those without a rail system. From 2001 to 2009, the estimated number of transit walkers rose from 7.5 million to 9.6 million (a 28% increase); those whose transit-associated walking time was 30 minutes or more increased from approximately 2.6 million to 3.4 million (a 31% increase). - Transit wal

mmuting to School: An Observational Evaluation in Five US Communities. J Phys Act Health. Epublished. - We assessed changes in transit-associated walking in the United States from 2001 to 2009 and documented their importance to public health. - We examined transit walk times using the National Household Travel Survey, a telephone survey administered by the US Department of Transportation to examine travel behavior in the United States. - People are more likely to transit walk if they are from lower income households, are non-White, and live in large urban areas with access to rail systems. Transit walkers in large urban areas with a rail system were 72% more likely to transit walk 30 minutes or more per day than were those without a rail system. From 2001 to 2009, the estimated number of transit walkers rose from 7.5 million to 9.6 million (a 28% increase); those whose transit-associated walking time was 30 minutes or more increased from approximately 2.6 million to 3.4 million (a 31% increase). - Transit walking contributes to meeting physical activity recommendations. Study results may contribute to transportation-related health impact assessment studies evaluating the impact of proposed transit systems on physical activity, potentially influencing transportation planning decisions. Freeland AL, Banerjee SN, Dannenberg AL, Wendel AM. (2013). Walking associated with public transit: moving toward increased physical activity in the United States. Am J Public Health, 103(3), 536-542. doi: 10.2105/AJPH.2012.300912. - This study developed and tested an algorithm to classify accelerometer data as walking or non-walking using either GPS or travel diary data within a large sample of adults under free-living conditions. - Participants wore an accelerometer and a GPS unit, and concurrently completed a travel diary for 7 consecutive days. Physical activity (PA) bouts were identified using accelerometry count sequences. PA bouts were then classified as walking or non-walking based on a decision-tree algorithm consisting of

king contributes to meeting physical activity recommendations. Study results may contribute to transportation-related health impact assessment studies evaluating the impact of proposed transit systems on physical activity, potentially influencing transportation planning decisions. Freeland AL, Banerjee SN, Dannenberg AL, Wendel AM. (2013). Walking associated with public transit: moving toward increased physical activity in the United States. Am J Public Health, 103(3), 536-542. doi: 10.2105/AJPH.2012.300912. - This study developed and tested an algorithm to classify accelerometer data as walking or non-walking using either GPS or travel diary data within a large sample of adults under free-living conditions. - Participants wore an accelerometer and a GPS unit, and concurrently completed a travel diary for 7 consecutive days. Physical activity (PA) bouts were identified using accelerometry count sequences. PA bouts were then classified as walking or non-walking based on a decision-tree algorithm consisting of 7 classification scenarios. Algorithm reliability was examined relative to two independent analysts' classification of a 100-bout verification sample. The algorithm was then applied to the entire set of PA bouts. - The 706 participants' (mean age 51 years, 62% female, 80% non-Hispanic white, 70% college graduate or higher) yielded 4,702 person-days of data and had a total of 13,971 PA bouts. The algorithm showed a mean agreement of 95% with the independent analysts. It classified physical activity into 8,170 (58.5 %) walking bouts and 5,337 (38.2%) non-walking bouts; 464 (3.3%) bouts were not classified for lack of GPS and diary data. Nearly 70% of the walking bouts and 68% of the non-walking bouts were classified using only the objective accelerometer and GPS data. Travel diary data helped classify 30% of all bouts with no GPS data. The mean duration of PA bouts classified as walking was 15.2 min (SD=12.9). On average, participants had 1.7 walking bouts and 25.4 total walking minutes per day. - GPS and trave

7 classification scenarios. Algorithm reliability was examined relative to two independent analysts' classification of a 100-bout verification sample. The algorithm was then applied to the entire set of PA bouts. - The 706 participants' (mean age 51 years, 62% female, 80% non-Hispanic white, 70% college graduate or higher) yielded 4,702 person-days of data and had a total of 13,971 PA bouts. The algorithm showed a mean agreement of 95% with the independent analysts. It classified physical activity into 8,170 (58.5 %) walking bouts and 5,337 (38.2%) non-walking bouts; 464 (3.3%) bouts were not classified for lack of GPS and diary data. Nearly 70% of the walking bouts and 68% of the non-walking bouts were classified using only the objective accelerometer and GPS data. Travel diary data helped classify 30% of all bouts with no GPS data. The mean duration of PA bouts classified as walking was 15.2 min (SD=12.9). On average, participants had 1.7 walking bouts and 25.4 total walking minutes per day. - GPS and travel diary information can be helpful in classifying most accelerometer-derived PA bouts into walking or non-walking behavior. Kang B, Moudon AV, Hurvitz PM, et al. (2013). Walking Objectively Measured: Classifying Accelerometer Data with GPS and Travel Diaries. Med Sci Sports Exerc. (e-published). - Given the health benefits of walking, there is interest in understanding how physical environments favor walking. Although GIS-derived measures of land-use mix, street connectivity, and residential density are commonly combined into indices to assess how conducive neighborhoods are to walking, field validation of these measures is limited. - To assess the relationship between audit- and GIS-derived measures of overall neighborhood walkability and between objective (audit- and GIS-derived) and participant-reported measures of walkability. - Walkability assessments were conducted in 2009. Street-level audits were conducted using a modified version of the Pedestrian Environmental Data Scan. GIS analyses were used to de

l diary information can be helpful in classifying most accelerometer-derived PA bouts into walking or non-walking behavior. Kang B, Moudon AV, Hurvitz PM, et al. (2013). Walking Objectively Measured: Classifying Accelerometer Data with GPS and Travel Diaries. Med Sci Sports Exerc. (e-published). - Given the health benefits of walking, there is interest in understanding how physical environments favor walking. Although GIS-derived measures of land-use mix, street connectivity, and residential density are commonly combined into indices to assess how conducive neighborhoods are to walking, field validation of these measures is limited. - To assess the relationship between audit- and GIS-derived measures of overall neighborhood walkability and between objective (audit- and GIS-derived) and participant-reported measures of walkability. - Walkability assessments were conducted in 2009. Street-level audits were conducted using a modified version of the Pedestrian Environmental Data Scan. GIS analyses were used to derive land-use mix, street connectivity, and residential density. Participant perceptions were assessed using a self-administered questionnaire. Audit, GIS, and participant-reported indices of walkability were calculated. Spearman correlation coefficients were used to assess the relationships between measures. All analyses were conducted in 2012. - The correlation between audit- and GIS-derived measures of overall walkability was high (R=0.7 [95% CI=0.6, 0.8]); the correlations between objective (audit and GIS-derived) and participant-reported measures were low (R=0.2 [95% CI=0.06, 0.3]; R=0.2 [95% CI=0.04, 0.3], respectively). For comparable audit and participant-reported items, correlations were higher for items that appeared more objective (e.g., sidewalk presence, R=0.4 [95% CI=0.3, 0.5], versus safety, R=0.1 [95% CI=0.003, 0.3]). - The GIS-derived measure of walkability correlated well with the in-field audit, suggesting that it is reasonable to use GIS-derived measures in place of more labor-intensive au

rive land-use mix, street connectivity, and residential density. Participant perceptions were assessed using a self-administered questionnaire. Audit, GIS, and participant-reported indices of walkability were calculated. Spearman correlation coefficients were used to assess the relationships between measures. All analyses were conducted in 2012. - The correlation between audit- and GIS-derived measures of overall walkability was high (R=0.7 [95% CI=0.6, 0.8]); the correlations between objective (audit and GIS-derived) and participant-reported measures were low (R=0.2 [95% CI=0.06, 0.3]; R=0.2 [95% CI=0.04, 0.3], respectively). For comparable audit and participant-reported items, correlations were higher for items that appeared more objective (e.g., sidewalk presence, R=0.4 [95% CI=0.3, 0.5], versus safety, R=0.1 [95% CI=0.003, 0.3]). - The GIS-derived measure of walkability correlated well with the in-field audit, suggesting that it is reasonable to use GIS-derived measures in place of more labor-intensive audits. Interestingly, neither audit- nor GIS-derived measures correlated well with participants’ perceptions of walkability. Hajna, Samantha, MSc, Kaberi Dasgupta, MD, MSc, FRCPC, Max Halparin, BA, Nancy A. Ross, PhD. (2012). Neighborhood Walkability: Field Validation of Geographic Information System Measures. American Journal of Preventive Medicine, 44(6), e51-e55. doi: 10.1016/j.amepre.2013.01.033 This report summarizes findings associated with the successful implementation of a Safe Routes to School program in an elementary school in metropolitan Atlanta, GA between 2008–2010. Elements of the program that led to its success may inform future policy efforts related to active transport to school. This was a multilevel, multi-sector, intervention involving education, community capacity building, enablement and reinforcement through supportive environments and evaluation. Elements and results included: - Safe Routes to School Task Force: Parent volunteers formed a Safe Routes to School Task Force comprising the

dits. Interestingly, neither audit- nor GIS-derived measures correlated well with participants’ perceptions of walkability. Hajna, Samantha, MSc, Kaberi Dasgupta, MD, MSc, FRCPC, Max Halparin, BA, Nancy A. Ross, PhD. (2012). Neighborhood Walkability: Field Validation of Geographic Information System Measures. American Journal of Preventive Medicine, 44(6), e51-e55. doi: 10.1016/j.amepre.2013.01.033 This report summarizes findings associated with the successful implementation of a Safe Routes to School program in an elementary school in metropolitan Atlanta, GA between 2008–2010. Elements of the program that led to its success may inform future policy efforts related to active transport to school. This was a multilevel, multi-sector, intervention involving education, community capacity building, enablement and reinforcement through supportive environments and evaluation. Elements and results included: - Safe Routes to School Task Force: Parent volunteers formed a Safe Routes to School Task Force comprising the school principal, nurse, and physical education teacher, as well as the county police, public works staff, board of health, and a county commissioner. This Task Force formed the basis of a movement to increase social capital at the community, school, family, and the individual level in order to shift the entire school community culture toward one of active transport. - Education: An informed and engaged community participated on its own behalf. Students, parents, school staff and faculty focused on Safe Routes to School goals of increasing walking roundtrip to school, decreasing traffic, and improving air quality around school. Pedestrian safety education was provided through the Physical Education program. The PTA and local churches were involved. Maps were provided of best walking routes and an extensive publicity campaign was undertaken. - Various local and federal resources were available to help support community infrastructure projects. Interactive Community Police and infrastructure improvements helpe

school principal, nurse, and physical education teacher, as well as the county police, public works staff, board of health, and a county commissioner. This Task Force formed the basis of a movement to increase social capital at the community, school, family, and the individual level in order to shift the entire school community culture toward one of active transport. - Education: An informed and engaged community participated on its own behalf. Students, parents, school staff and faculty focused on Safe Routes to School goals of increasing walking roundtrip to school, decreasing traffic, and improving air quality around school. Pedestrian safety education was provided through the Physical Education program. The PTA and local churches were involved. Maps were provided of best walking routes and an extensive publicity campaign was undertaken. - Various local and federal resources were available to help support community infrastructure projects. Interactive Community Police and infrastructure improvements helped improve safety along routes to school. - Built environment improvements to increase active transport to school benefited the surrounding community as nearly 40% of communities are within ½ mile of a public school. Five crosswalks were restriped and raised walking intersections and new traffic lights were installed. - Parental surveys confirmed increased rates of walking to school (18% to 42% in two years) and parental perceptions of health benefits and enjoyment of walking increased. Rates of walking home did not change. Susan Henderson, Robin Tanner, Normal Klanderman, Abby Mattera, Lindey Martin Webb, John Steward. (2013). Safe Routes to School: A Public Health Practice Success Story—Atlanta, 2008-2010. Journal of Physical Activity and Health, 2013, 10, 141-142. - This novel interdisciplinary collaboration between public health and computer science provides automatic analysis of existing public data feeds to quantify the impact of built environment intervention on increasing bike travel mode share. - The

d improve safety along routes to school. - Built environment improvements to increase active transport to school benefited the surrounding community as nearly 40% of communities are within ½ mile of a public school. Five crosswalks were restriped and raised walking intersections and new traffic lights were installed. - Parental surveys confirmed increased rates of walking to school (18% to 42% in two years) and parental perceptions of health benefits and enjoyment of walking increased. Rates of walking home did not change. Susan Henderson, Robin Tanner, Normal Klanderman, Abby Mattera, Lindey Martin Webb, John Steward. (2013). Safe Routes to School: A Public Health Practice Success Story—Atlanta, 2008-2010. Journal of Physical Activity and Health, 2013, 10, 141-142. - This novel interdisciplinary collaboration between public health and computer science provides automatic analysis of existing public data feeds to quantify the impact of built environment intervention on increasing bike travel mode share. - The Archive of Many Outdoor Scenes (AMOS) has archived over 225 million images of outdoor environments from more than 12,000 public webcams since 2006. Using the publicly available webcams and a custom web crawler (similar to the web search engine or Google), webcam images are captured at the rate of one image per camera per hour and given a time stamp. Many of the locations have had built environment improvements such as complete streets, bike share startups or walking school bus programs. AMOS is able to document and allow quantification of population behavior changes following the built environment modification. - The intersection of Pennsylvania Ave NW and 9th ST NW in Washington, DC where bike lanes were installed was chosen as a location to monitor transportation mode share comparing the first workweek or June 2009 and the first week of June 2010 (pre-bicycle lane and post-bicycle lane). - Amazon Mechanical Turk (MTurk) website was used to crowd-source the image annotation. MTurks are simple tasks not yet c

Archive of Many Outdoor Scenes (AMOS) has archived over 225 million images of outdoor environments from more than 12,000 public webcams since 2006. Using the publicly available webcams and a custom web crawler (similar to the web search engine or Google), webcam images are captured at the rate of one image per camera per hour and given a time stamp. Many of the locations have had built environment improvements such as complete streets, bike share startups or walking school bus programs. AMOS is able to document and allow quantification of population behavior changes following the built environment modification. - The intersection of Pennsylvania Ave NW and 9th ST NW in Washington, DC where bike lanes were installed was chosen as a location to monitor transportation mode share comparing the first workweek or June 2009 and the first week of June 2010 (pre-bicycle lane and post-bicycle lane). - Amazon Mechanical Turk (MTurk) website was used to crowd-source the image annotation. MTurks are simple tasks not yet computer automated. MTurk workers were paid US $0.01, in March 2012 to count each pedestrian, cyclist, and vehicle in a photograph. Each image was counted 5 unique times (n=1200), completed in less than 8 hours. The counts per transportation mode were downloaded to SPSSv.19 for analysis. Results showed a statistically significant difference in transportation mode share between the two years: no significant increase in pedestrians but a four-fold increase in the number of cyclists per scene. - The investigators conclude that the use of AMOS and MTurks offer an inexpensive ($12.00 for this study) opportunity to quantify behavior change impact following built environment changes. Future plans include monitoring other locations in the Washington DC Capitol Bikeshare program and developing computer algorithms to automate the counting process. Hipp, J. Aaron; Adlakha, Deepti; Chang, Bill; Eyler, Amy A.; and Pless, Robert B. (2013). "Emerging Technologies: Webcams and Crowd- Sourcing to Identify Active Transportation

omputer automated. MTurk workers were paid US $0.01, in March 2012 to count each pedestrian, cyclist, and vehicle in a photograph. Each image was counted 5 unique times (n=1200), completed in less than 8 hours. The counts per transportation mode were downloaded to SPSSv.19 for analysis. Results showed a statistically significant difference in transportation mode share between the two years: no significant increase in pedestrians but a four-fold increase in the number of cyclists per scene. - The investigators conclude that the use of AMOS and MTurks offer an inexpensive ($12.00 for this study) opportunity to quantify behavior change impact following built environment changes. Future plans include monitoring other locations in the Washington DC Capitol Bikeshare program and developing computer algorithms to automate the counting process. Hipp, J. Aaron; Adlakha, Deepti; Chang, Bill; Eyler, Amy A.; and Pless, Robert B. (2013). "Emerging Technologies: Webcams and Crowd- Sourcing to Identify Active Transportation" (2013). Brown School Faculty Publications (Paper 3). - The authors indicate that in the United States, development in the past 60 years has turned away from the traditional compact, walkable city or town toward a more dispersed, automobile-centric pattern that makes travel by any means except private vehicle impractical and inconvenient. - The article explores what makes the United States so different from European countries in which walking and bicycling is more prevalent. - To plan sustainable—and healthful—human environments, and to determine the most cost-effective measures to encourage more walking and bicycling, more must be known about the various influences on bicycling and walking behavior. - The article includes an overview of data and planning tools helpful for non-motorized travel, a wide array of walking and bicycling data, an examination of the influence of the natural and built environment, attitudes and perceptions towards walking and bicycling, and questions for future research. - The artic

" (2013). Brown School Faculty Publications (Paper 3). - The authors indicate that in the United States, development in the past 60 years has turned away from the traditional compact, walkable city or town toward a more dispersed, automobile-centric pattern that makes travel by any means except private vehicle impractical and inconvenient. - The article explores what makes the United States so different from European countries in which walking and bicycling is more prevalent. - To plan sustainable—and healthful—human environments, and to determine the most cost-effective measures to encourage more walking and bicycling, more must be known about the various influences on bicycling and walking behavior. - The article includes an overview of data and planning tools helpful for non-motorized travel, a wide array of walking and bicycling data, an examination of the influence of the natural and built environment, attitudes and perceptions towards walking and bicycling, and questions for future research. - The article also links to several other publications that may be useful for active transportation practitioners: - NCHRP Project 8-78 guidebook Estimating Bicycling and pedestrian Demand for Planning and Project Development http://apps.trb.org/cmsfeed/TRBNetProjectDisplay.asp?ProjectID=2707 - American Association of State Highway and Transportation Officials (AASHTO) Guide for the Development of Bicycle Facilities, 4th Edition, https://bookstore.transportation.org/item_details.aspx?ID=1943 - NCHRP (National Cooperative Highway Research Project) Report 500 series Vol 10 and 18 are Guides for Reducing Collisions Involving Pedestrians and a second Guide to Reducing Collisions Involving Bicycles. More information can be found at www.trb.org/Main/Public/Blurbs/152868.aspx - Traveler Response to Transportation system Changes, Chpt 16: Pedestrian and Bicycle Facilities available online at www.trb.org/Main/Blurbs/167122.aspx Kuzmyak R. Dill J. (2012). Walking and Bicycling in the United States: The Who, What, Where, and Why.

le also links to several other publications that may be useful for active transportation practitioners: - NCHRP Project 8-78 guidebook Estimating Bicycling and pedestrian Demand for Planning and Project Development http://apps.trb.org/cmsfeed/TRBNetProjectDisplay.asp?ProjectID=2707 - American Association of State Highway and Transportation Officials (AASHTO) Guide for the Development of Bicycle Facilities, 4th Edition, https://bookstore.transportation.org/item_details.aspx?ID=1943 - NCHRP (National Cooperative Highway Research Project) Report 500 series Vol 10 and 18 are Guides for Reducing Collisions Involving Pedestrians and a second Guide to Reducing Collisions Involving Bicycles. More information can be found at www.trb.org/Main/Public/Blurbs/152868.aspx - Traveler Response to Transportation system Changes, Chpt 16: Pedestrian and Bicycle Facilities available online at www.trb.org/Main/Blurbs/167122.aspx Kuzmyak R. Dill J. (2012). Walking and Bicycling in the United States: The Who, What, Where, and Why. TR News, 280(May/June), 4-17. - This pilot study examined the effects of a teacher-taught, locomotor skill (LMS)-based physical activity (PA) program on the LMS and PA levels of minority preschooler-aged children. - Eight low-socioeconomic status preschool classrooms were randomized into LMS-PA (LMS-oriented lesson plans) or control group (supervised free playtime). Interventions were delivered for 30 min/day, five days/week for six months. Changes in PA (accelerometer) and LMS variables were assessed with MANCOVA. - LMS-PA group exhibited a significant reduction in during-preschool and total daily percent time spent in sedentary activity. LMS-PA group also exhibited significant improvement in leaping skills. No other, significant changes were observed. The implementation of a teacher-taught, LMS-based PA program could potentially improve LMS and reduce sedentary time of minority preschoolers. Alhassan, S., O. Nwaokelemeh, et al. (2012). "Effects of locomotor skill program on minority preschoolers' physical a

TR News, 280(May/June), 4-17. - This pilot study examined the effects of a teacher-taught, locomotor skill (LMS)-based physical activity (PA) program on the LMS and PA levels of minority preschooler-aged children. - Eight low-socioeconomic status preschool classrooms were randomized into LMS-PA (LMS-oriented lesson plans) or control group (supervised free playtime). Interventions were delivered for 30 min/day, five days/week for six months. Changes in PA (accelerometer) and LMS variables were assessed with MANCOVA. - LMS-PA group exhibited a significant reduction in during-preschool and total daily percent time spent in sedentary activity. LMS-PA group also exhibited significant improvement in leaping skills. No other, significant changes were observed. The implementation of a teacher-taught, LMS-based PA program could potentially improve LMS and reduce sedentary time of minority preschoolers. Alhassan, S., O. Nwaokelemeh, et al. (2012). "Effects of locomotor skill program on minority preschoolers' physical activity levels." Pediatrc Exercise Science 24(3): 435-449. - Washington State Department of Transportation released a report that assessed the Safe Routes to School program in five states: Florida, Mississippi, Texas, Washington, and Wisconsin. - A database of all SRTS projects announced for funding and all schools affected by these projects were developed. The database was analyzed to (1) quantify the SRTS programs’ impact in the five states and compare them to SRTS programs nationally, (2) assess the SRTS programs’ effectiveness in increasing rates of walking and bicycling to school, and (3) identify characteristics of SRTS projects associated with greater increases in walking and bicycling to school. - The results of this study offer preliminary evidence that the SRTS program is achieving one of its primary goals of increasing rates of walking and bicycling to school and that SRTS funds are delivering a return on investment. - Key finding from this study: In the five states, more than 1400 schools and 781,

ctivity levels." Pediatrc Exercise Science 24(3): 435-449. - Washington State Department of Transportation released a report that assessed the Safe Routes to School program in five states: Florida, Mississippi, Texas, Washington, and Wisconsin. - A database of all SRTS projects announced for funding and all schools affected by these projects were developed. The database was analyzed to (1) quantify the SRTS programs’ impact in the five states and compare them to SRTS programs nationally, (2) assess the SRTS programs’ effectiveness in increasing rates of walking and bicycling to school, and (3) identify characteristics of SRTS projects associated with greater increases in walking and bicycling to school. - The results of this study offer preliminary evidence that the SRTS program is achieving one of its primary goals of increasing rates of walking and bicycling to school and that SRTS funds are delivering a return on investment. - Key finding from this study: In the five states, more than 1400 schools and 781,000 children have been reached as a result of Safe Routes to School funding; this is roughly 11 percent of the pre-kindergarten through eighth grade public school population in the five states. - Key finding from this study: Engineering projects made up about 72 percent of the funding in the five states, with sidewalk projects featured in about 69 percent of these projects. Interestingly, the engineering projects that were on smaller scales (affected fewer schools and students) and included encouragement and education components tended to perform better. - Key finding from this study: Rates of walking increased by 45 percent, bicycling increased by 24 percent, and all active travel to school increased by 37 percent in these five states. - The study findings suggested that Safe Routes to School projects may be more effective at encouraging bicycling to school where few children already do so. - Poor lifestyle behaviors, including suboptimal diet, physical inactivity, and tobacco use, are leading causes of prev

000 children have been reached as a result of Safe Routes to School funding; this is roughly 11 percent of the pre-kindergarten through eighth grade public school population in the five states. - Key finding from this study: Engineering projects made up about 72 percent of the funding in the five states, with sidewalk projects featured in about 69 percent of these projects. Interestingly, the engineering projects that were on smaller scales (affected fewer schools and students) and included encouragement and education components tended to perform better. - Key finding from this study: Rates of walking increased by 45 percent, bicycling increased by 24 percent, and all active travel to school increased by 37 percent in these five states. - The study findings suggested that Safe Routes to School projects may be more effective at encouraging bicycling to school where few children already do so. - Poor lifestyle behaviors, including suboptimal diet, physical inactivity, and tobacco use, are leading causes of preventable diseases globally. Although even modest population shifts in risk substantially alter health outcomes, the optimal population-level approaches to improve lifestyle are not well established. - In this paper, the authors systematically reviewed and graded the current scientific evidence for effective population approaches to improve dietary habits, increase physical activity, and reduce tobacco use. - Strategies were considered in 6 broad domains: (1) Media and educational campaigns; (2) labeling and consumer information; (3) taxation, subsidies, and other economic incentives; (4) school and workplace approaches; (5) local environmental changes; and (6) direct restrictions and mandates. The writing group also reviewed the potential contributions of healthcare systems and surveillance systems to behavior change efforts. - Several specific population interventions were identified, providing a set of specific evidence-based strategies that deserve close attention and prioritization for wider implementation

entable diseases globally. Although even modest population shifts in risk substantially alter health outcomes, the optimal population-level approaches to improve lifestyle are not well established. - In this paper, the authors systematically reviewed and graded the current scientific evidence for effective population approaches to improve dietary habits, increase physical activity, and reduce tobacco use. - Strategies were considered in 6 broad domains: (1) Media and educational campaigns; (2) labeling and consumer information; (3) taxation, subsidies, and other economic incentives; (4) school and workplace approaches; (5) local environmental changes; and (6) direct restrictions and mandates. The writing group also reviewed the potential contributions of healthcare systems and surveillance systems to behavior change efforts. - Several specific population interventions were identified, providing a set of specific evidence-based strategies that deserve close attention and prioritization for wider implementation. School-related interventions included increased availability and types of school playground spaces and equipment, increased number of PE classes, and revised PE curricula to increase time in at least moderate activity. - This systematic review identified and graded the evidence for a range of population-based strategies to promote lifestyle change. The findings provide a framework for policy makers, advocacy groups, researchers, clinicians, communities, and other stakeholders to understand and implement the most effective approaches. New strategic initiatives and partnerships are needed to translate this evidence into action. Mozaffarian, D., A. Afshin, et al. (2012). Population Approaches to Improve Diet, Physical Activity, and Smoking Habits A Scientific Statement From the American Heart Association. Circulation 126(12):1514-1563. - The recess environment in schools has been identified as an integral part of school-based programs to enhance physical activity (PA). The purpose of this study was to report p

. School-related interventions included increased availability and types of school playground spaces and equipment, increased number of PE classes, and revised PE curricula to increase time in at least moderate activity. - This systematic review identified and graded the evidence for a range of population-based strategies to promote lifestyle change. The findings provide a framework for policy makers, advocacy groups, researchers, clinicians, communities, and other stakeholders to understand and implement the most effective approaches. New strategic initiatives and partnerships are needed to translate this evidence into action. Mozaffarian, D., A. Afshin, et al. (2012). Population Approaches to Improve Diet, Physical Activity, and Smoking Habits A Scientific Statement From the American Heart Association. Circulation 126(12):1514-1563. - The recess environment in schools has been identified as an integral part of school-based programs to enhance physical activity (PA). The purpose of this study was to report pilot findings on the extent to which the Ready for Recess intervention was associated with a different amount of increase in moderate to vigorous PA (MPVA) during recess and the rest of the school day between girls and boys, and between nonwhites and whites. - The Ready for Recess intervention modified the recess environment of schools by providing staff training and recreational equipment. The MPVA levels of 3rd, 4th, and 5th grade students (n = 93) at 2 schools were measured pre- and post-intervention using ActiGraph accelerometers. Multiple regression models with robust variance were utilized to test for the interaction of intervention with gender and race/ethnicity. - The intervention was associated with an adjusted increase of 4.7 minutes (P <.001) in moderate/vigorous PA during recess. There was no evidence that this effect varied by gender (P = .944) or race (P = .731). The intervention was also associated with an adjusted increase of 29.6 minutes (P < .001) in moderate/vigorous PA during rest of the s

ilot findings on the extent to which the Ready for Recess intervention was associated with a different amount of increase in moderate to vigorous PA (MPVA) during recess and the rest of the school day between girls and boys, and between nonwhites and whites. - The Ready for Recess intervention modified the recess environment of schools by providing staff training and recreational equipment. The MPVA levels of 3rd, 4th, and 5th grade students (n = 93) at 2 schools were measured pre- and post-intervention using ActiGraph accelerometers. Multiple regression models with robust variance were utilized to test for the interaction of intervention with gender and race/ethnicity. - The intervention was associated with an adjusted increase of 4.7 minutes (P <.001) in moderate/vigorous PA during recess. There was no evidence that this effect varied by gender (P = .944) or race (P = .731). The intervention was also associated with an adjusted increase of 29.6 minutes (P < .001) in moderate/vigorous PA during rest of the school day. While this effect did not vary by gender, there was some evidence (P = .034) that nonwhites benefited more from the intervention than whites. - Simple strategies such as staff training and recreational equipment may be an effective way to increase PA in children (despite gender or ethnicity) during recess time as well as during the rest of the school day. Siahpush, M., J. L. Huberty, et al. (2012). Does the Effect of a School Recess Intervention on Physical Activity Vary by Gender or Race? Results From the Ready for Recess Pilot Study. Journal of Public Health Management and Practice 18(5): 416-422. - This article reports on a study that explored the barriers that prevent parents from allowing their children to commute to school. - The authors used data from parents of school children in Illinois, U.S., as reported in the National Safe Routes to School Parent Surveys. - The study finds that the top barriers for both urban and suburban children were intersection safety and traffic speed/volume. Dist

chool day. While this effect did not vary by gender, there was some evidence (P = .034) that nonwhites benefited more from the intervention than whites. - Simple strategies such as staff training and recreational equipment may be an effective way to increase PA in children (despite gender or ethnicity) during recess time as well as during the rest of the school day. Siahpush, M., J. L. Huberty, et al. (2012). Does the Effect of a School Recess Intervention on Physical Activity Vary by Gender or Race? Results From the Ready for Recess Pilot Study. Journal of Public Health Management and Practice 18(5): 416-422. - This article reports on a study that explored the barriers that prevent parents from allowing their children to commute to school. - The authors used data from parents of school children in Illinois, U.S., as reported in the National Safe Routes to School Parent Surveys. - The study finds that the top barriers for both urban and suburban children were intersection safety and traffic speed/volume. Distance from school had a greater impact on the walking or bicycling to school habits of suburban students compared to urban students. - The authors contend that actively commuting to school gives children the opportunity to explore nature, get exercise, and develop cognitive skills. With the barriers to active commuting to school identified, the Safe Routes to School Programs in Illinois can target their resources effectively to encourage children and their parents to consider walking and biking alternatives for trips to and from school. Fries, R., E. Sykut, et al. (2012). Barriers Influencing Illinois Children School Travel Mode Choices. Advances in Transportation Studies 27. - This study examined the relationship between state laws requiring minimum bussing distances, hazardous route exemptions, sidewalks, crossing guards, speed zones, and traffic control measures around schools and active travel to school (ATS) policies and practices in nationally representative samples of U.S. public elementary schools betwe

ance from school had a greater impact on the walking or bicycling to school habits of suburban students compared to urban students. - The authors contend that actively commuting to school gives children the opportunity to explore nature, get exercise, and develop cognitive skills. With the barriers to active commuting to school identified, the Safe Routes to School Programs in Illinois can target their resources effectively to encourage children and their parents to consider walking and biking alternatives for trips to and from school. Fries, R., E. Sykut, et al. (2012). Barriers Influencing Illinois Children School Travel Mode Choices. Advances in Transportation Studies 27. - This study examined the relationship between state laws requiring minimum bussing distances, hazardous route exemptions, sidewalks, crossing guards, speed zones, and traffic control measures around schools and active travel to school (ATS) policies and practices in nationally representative samples of U.S. public elementary schools between 2007–2009. The state laws and school data were compiled through primary legal research and annual mail-back surveys of principals, respectively. - A pooled, cross-sectional analysis examined the relationship between the state laws and the school policies and practices. - A stacked, cross-sectional data set containing 1967 schools over the combined period, 2007–2009, comprised the final study sample (with 578, 749, and 641 schools included in each of the three corresponding study years). - Multivariate logistic and zero-inflated poisson regression indicated that all state law categories (except for sidewalks) relate to ATS. These laws should be considered in addition to formal Safe Routes to School programs as possible influences on ATS. - Nearly 40 percent of schools were located in states with minimum bussing distance requirements; 23.4 percent were located in states with hazardous route exemptions. - More schools allowed all students to walk to school if the state had a minimum bussing distance law of great

en 2007–2009. The state laws and school data were compiled through primary legal research and annual mail-back surveys of principals, respectively. - A pooled, cross-sectional analysis examined the relationship between the state laws and the school policies and practices. - A stacked, cross-sectional data set containing 1967 schools over the combined period, 2007–2009, comprised the final study sample (with 578, 749, and 641 schools included in each of the three corresponding study years). - Multivariate logistic and zero-inflated poisson regression indicated that all state law categories (except for sidewalks) relate to ATS. These laws should be considered in addition to formal Safe Routes to School programs as possible influences on ATS. - Nearly 40 percent of schools were located in states with minimum bussing distance requirements; 23.4 percent were located in states with hazardous route exemptions. - More schools allowed all students to walk to school if the state had a minimum bussing distance law of greater than one mile or a law requiring sidewalks or traffic control measures. - The odds of zero students walking/biking to school were 68 percent lower in states requiring crossing guards and 55 percent lower in states requiring speed zones. Chriqui, JF, Taber, DR, et al. (2012). “The impact of state safe routes to school-related laws on active travel to school policies and practices in U.S. elementary schools.” Health & Place 18(1): 8-15. - Walking and bicycling are important but underused modes of transportation in the United States. Road design influences how much walking and bicycling takes place along streets and roads. Currently, numerous national policy initiatives, including Safe Routes to School and Complete Streets, are attempting to improve pedestrian and bicycling infrastructure and “friendliness.” However, no state has completed a systematic assessment of its streets to determine how amenable they are to walking and bicycling. This statewide study was undertaken to assess how accessible and friendl

er than one mile or a law requiring sidewalks or traffic control measures. - The odds of zero students walking/biking to school were 68 percent lower in states requiring crossing guards and 55 percent lower in states requiring speed zones. Chriqui, JF, Taber, DR, et al. (2012). “The impact of state safe routes to school-related laws on active travel to school policies and practices in U.S. elementary schools.” Health & Place 18(1): 8-15. - Walking and bicycling are important but underused modes of transportation in the United States. Road design influences how much walking and bicycling takes place along streets and roads. Currently, numerous national policy initiatives, including Safe Routes to School and Complete Streets, are attempting to improve pedestrian and bicycling infrastructure and “friendliness.” However, no state has completed a systematic assessment of its streets to determine how amenable they are to walking and bicycling. This statewide study was undertaken to assess how accessible and friendly Hawaii roads are to these 2 activities. - The authors randomly selected street segments in Hawaii’s 4 counties and then completed objective assessments using the Pedestrian Environmental Data Scan. They audited 321 segments, and interrater reliability was adequate across all measures. Streets were coded as high (42.4%) or low capacity (57.6%) depending on how much vehicular traffic the street was designed to accommodate. Outcome measures included street accommodations (ie, sidewalks and crossing aids) and pedestrian and bicyclist use. - Most high-capacity streets had sidewalks (66%). These sidewalks were usually in good condition, contiguous, and had traffic control devices and pedestrian signals. Most low-capacity roads did not have sidewalks (63.4%). Bicycling facilities were limited (<10%) on both types of roads. Pedestrian and bicycle traffic was related to mixed use, including both residential and retail space, and to pedestrian and bicycling infrastructure. - Road segments in Hawaii with more infrastr

y Hawaii roads are to these 2 activities. - The authors randomly selected street segments in Hawaii’s 4 counties and then completed objective assessments using the Pedestrian Environmental Data Scan. They audited 321 segments, and interrater reliability was adequate across all measures. Streets were coded as high (42.4%) or low capacity (57.6%) depending on how much vehicular traffic the street was designed to accommodate. Outcome measures included street accommodations (ie, sidewalks and crossing aids) and pedestrian and bicyclist use. - Most high-capacity streets had sidewalks (66%). These sidewalks were usually in good condition, contiguous, and had traffic control devices and pedestrian signals. Most low-capacity roads did not have sidewalks (63.4%). Bicycling facilities were limited (<10%) on both types of roads. Pedestrian and bicycle traffic was related to mixed use, including both residential and retail space, and to pedestrian and bicycling infrastructure. - Road segments in Hawaii with more infrastructure and types of use, including single-family houses, apartment complexes, restaurants, office buildings, and industrial buildings, are used more by pedestrians and bicyclists. Maddock JE, Ramirez V, Heinrich KM, Zhang M, Brunner IM. (2012). “A Statewide Observational Assessment of the Pedestrian and Cycling Environment in Hawaii, 2010.” Preventing Chronic Disease. - This paper examines parents' responses to key factors associated with mode choices for school trips. The research was conducted with parents of elementary school students in Denver Colorado as part of a larger investigation of school travel. - School-based active travel programs aim to encourage students to walk or bike to school more frequently. To that end, planning research has identified an array of factors associated with parents' decisions to drive children to school. Many findings are interpreted as ‘barriers’ to active travel, implying that parents have similar objectives with respect to travel mode choices and that parents respond sim

ucture and types of use, including single-family houses, apartment complexes, restaurants, office buildings, and industrial buildings, are used more by pedestrians and bicyclists. Maddock JE, Ramirez V, Heinrich KM, Zhang M, Brunner IM. (2012). “A Statewide Observational Assessment of the Pedestrian and Cycling Environment in Hawaii, 2010.” Preventing Chronic Disease. - This paper examines parents' responses to key factors associated with mode choices for school trips. The research was conducted with parents of elementary school students in Denver Colorado as part of a larger investigation of school travel. - School-based active travel programs aim to encourage students to walk or bike to school more frequently. To that end, planning research has identified an array of factors associated with parents' decisions to drive children to school. Many findings are interpreted as ‘barriers’ to active travel, implying that parents have similar objectives with respect to travel mode choices and that parents respond similarly and consistently to external conditions. While the conclusions are appropriate in forecasting demand and mode share with large populations, they are generally too coarse for programs that aim to influence travel behavior with individuals and small groups. - This research uses content analysis of interview transcripts to examine the contexts of factors associated with parents' mode choices for trips to and from elementary school. Short, semi-structured interviews were conducted with 65 parents from 12 Denver Public Elementary Schools that had been selected to receive 2007–08 Safe Routes to School non-infrastructure grants. Transcripts were analyzed using Nvivo 8.0 to find out how parents respond to selected factors that are often described in planning literature as ‘barriers’ to active travel. - Regular active travel appears to diminish parents' perceptions of barriers so that negotiation becomes second nature. Findings from this study suggest that intervention should build capacity and inclination in o

ilarly and consistently to external conditions. While the conclusions are appropriate in forecasting demand and mode share with large populations, they are generally too coarse for programs that aim to influence travel behavior with individuals and small groups. - This research uses content analysis of interview transcripts to examine the contexts of factors associated with parents' mode choices for trips to and from elementary school. Short, semi-structured interviews were conducted with 65 parents from 12 Denver Public Elementary Schools that had been selected to receive 2007–08 Safe Routes to School non-infrastructure grants. Transcripts were analyzed using Nvivo 8.0 to find out how parents respond to selected factors that are often described in planning literature as ‘barriers’ to active travel. - Regular active travel appears to diminish parents' perceptions of barriers so that negotiation becomes second nature. Findings from this study suggest that intervention should build capacity and inclination in order to increase rates of active travel. Zuniga, Kelly Draper. (2012). “From Barrier Elimination to Barrier Negotiation: A Qualitative Study of Parents’ Attitudes about Active Travel for Elementary School Trips” Transport Policy 20: 75–81. - Despite efforts to combat increasing rates of childhood obesity, the problem is worsening. Safe Routes to School (SRTS), an international movement motivated by the childhood obesity epidemic, seeks to increase the number of children actively commuting (walking or biking) to school by funding projects that remove barriers preventing them from doing so. This article summarizes the evaluation of the first phase of an ongoing SRTS program in California and discusses ways to enhance data collection. - There is no requirement for funded SRTS programs to submit evaluation data to the California Department of Public Health, but some supply information on a voluntary basis. This study used de-identified data sent to the University of California, San Francisco. The information was o

rder to increase rates of active travel. Zuniga, Kelly Draper. (2012). “From Barrier Elimination to Barrier Negotiation: A Qualitative Study of Parents’ Attitudes about Active Travel for Elementary School Trips” Transport Policy 20: 75–81. - Despite efforts to combat increasing rates of childhood obesity, the problem is worsening. Safe Routes to School (SRTS), an international movement motivated by the childhood obesity epidemic, seeks to increase the number of children actively commuting (walking or biking) to school by funding projects that remove barriers preventing them from doing so. This article summarizes the evaluation of the first phase of an ongoing SRTS program in California and discusses ways to enhance data collection. - There is no requirement for funded SRTS programs to submit evaluation data to the California Department of Public Health, but some supply information on a voluntary basis. This study used de-identified data sent to the University of California, San Francisco. The information was on children's school transport modes and parents’ views on active commuting from the Arrival and Departure Tally Sheet and Parent Survey about Walking and Biking to School, instruments developed by the SRTS national center. - As of October 2010, 20% (n = 42) of grantees from 219 federally funded programs in California had voluntarily submitted evaluation data pertaining to 392 schools, including 63,078 unique parent records. - Findings: Regardless of weather conditions, day of week, or time of day, the relative pattern of school transport mode was consistent. A majority of children commuted in their family vehicle, and smaller percentages of children walked, carpooled, took the school bus, biked, or used public transportation. Chaufan, C., Yeh, J., Fox, P. (2012). “The Safe Routes to School Program in California: An Update.” American Journal of Public Health 102(6): e8–e11 - Researchers examined the extent to which differential traffic volume and road geometry can explain social inequalities in pedestrian, cyc

n children's school transport modes and parents’ views on active commuting from the Arrival and Departure Tally Sheet and Parent Survey about Walking and Biking to School, instruments developed by the SRTS national center. - As of October 2010, 20% (n = 42) of grantees from 219 federally funded programs in California had voluntarily submitted evaluation data pertaining to 392 schools, including 63,078 unique parent records. - Findings: Regardless of weather conditions, day of week, or time of day, the relative pattern of school transport mode was consistent. A majority of children commuted in their family vehicle, and smaller percentages of children walked, carpooled, took the school bus, biked, or used public transportation. Chaufan, C., Yeh, J., Fox, P. (2012). “The Safe Routes to School Program in California: An Update.” American Journal of Public Health 102(6): e8–e11 - Researchers examined the extent to which differential traffic volume and road geometry can explain social inequalities in pedestrian, cyclist, and motor vehicle occupant injuries across wealthy and poor urban areas. - They performed a multilevel observational study of all road users injured over 5 years (n = 19 568) at intersections (n = 17 498) in a large urban area (Island of Montreal, Canada). They considered intersection-level (traffic estimates, major roads, number of legs) and area-level (population density, commuting travel modes, household income) characteristics in multilevel Poisson regressions that nested intersections in 506 census tracts. - There were significantly more injured pedestrians, cyclists, and motor vehicle occupants at intersections in the poorest than in the richest areas. Controlling for traffic volume, intersection geometry, and pedestrian and cyclist volumes greatly attenuated the event rate ratios between intersections in the poorest and richest areas for injured pedestrians (−70%), cyclists (−44%), and motor vehicle occupants (−44%). - Roadway environment can explain a substantial portion of the excess rate of ro

list, and motor vehicle occupant injuries across wealthy and poor urban areas. - They performed a multilevel observational study of all road users injured over 5 years (n = 19 568) at intersections (n = 17 498) in a large urban area (Island of Montreal, Canada). They considered intersection-level (traffic estimates, major roads, number of legs) and area-level (population density, commuting travel modes, household income) characteristics in multilevel Poisson regressions that nested intersections in 506 census tracts. - There were significantly more injured pedestrians, cyclists, and motor vehicle occupants at intersections in the poorest than in the richest areas. Controlling for traffic volume, intersection geometry, and pedestrian and cyclist volumes greatly attenuated the event rate ratios between intersections in the poorest and richest areas for injured pedestrians (−70%), cyclists (−44%), and motor vehicle occupants (−44%). - Roadway environment can explain a substantial portion of the excess rate of road traffic injuries in the poorest urban areas. Morency, P., L. Gauvin, et al. (2012). "Neighborhood Social Inequalities in Road Traffic Injuries: The Influence of Traffic Volume and Road Design." American Journal of Public Health 102(6): 1112-1119. - Although a health impact assessment (HIA) is a tool that can provide decision makers with recommendations to promote positive health impacts and mitigate adverse health impacts of proposed projects and policies, it is not routinely conducted on most major projects or policies. - To make health a decision criterion for the Atlanta BeltLine, a multibillion-dollar transit, trails, parks, and redevelopment project, a HIA was conducted in 2005–2007 to anticipate and influence the BeltLine's effect on health determinants. - Changes in access and equity, environmental quality, safety, social capital, and physical activity were forecast, and steps to maximize health benefits and reduce negative effects were recommended. - Key recommendations included giving priority to