A linear model for determining coordination of two adjacent signalized intersections
Purpose – Urban networks are usually divided into several open or closed sub‐networks. Signal coordination has been recognized as one of the most efficient methods of controlling sub‐networks that have independently optimized timing plans. However, coordinating adjacent intersections in a network is a basic prerequisite to optimizing signal‐timing plans for sub‐networks. This paper aims to develop a linear model to support decisions regarding coordination of adjacent signals.Design/methodology/approach – This paper aims to develop a linear model to support decisions regarding coordination of adjacent signals. The tests of this model which using the field data differ from those for calibration from various roadways, indicating that the model has transferability. Evaluations using microscopic simulation show that the model can objectively determine whether or not to interconnect adjacent signals depending on various traffic demands.Findings – The model was calibrated by stepwise regression analysis with a t...
SUBDIVISION OF SIGNAL SYSTEMS INTO CONTROL AREAS
QUESTIONS THAT FACE TRAFFIC ENGINEERS ARE DISCUSSED. THEY ARE, NAMELY, WHETHER OR NOT TO COORDINATE THE TIMING AT TWO ADJACENT SIGNALIZED INTERSECTIONS, AND WHETHER OR NOT TO SUBDIVIDE A SIGNALIZED NETWORK INTO TWO OR MORE URBAN TRAFFIC CONTROL AREAS; HOW TO LOCATE CANDIDATE SUBDIVISION BOUNDARIES WHICH MIGHT PROVE BENEFICIAL; AND AND HOW TO DETERMINE WHETHER OR NOT SUBDIVISION ALONG A PARTICULAR BOUNDARY IS BENEFICIAL. ANALYTICAL METHODOLOGY EMPLOYING COMPUTER ANALYSIS PROGRAMS HAVE BEEN USED TO RESOLVE THESE QUESTIONS. EXPERIMENTS HAVE ESTABLISHED THAT THE DISPERSION EXPERIENCED WITHIN A PLATOON OF TRAFFIC RELEASED FROM A SIGNALIZED INTERSECTION INCREASES WITH THE DISTANCE TRAVELLED. AS A RESULT, THE BENEFITS TO BE DERIVED FROM COORDINATING ADJACENT SIGNALIZED INTERSECTIONS TENDS TO DIMINISH AS THE DISTANCE BETWEEN SIGNALIZED INTERSECTIONS IS INCREASED. A COUPLING INDEX IS DEFINED AND THE APPLICATION OF THE WINSTON-SALEM STUDY IS DESCRIBED. ONE OF THE OBJECTIVES OF THIS STUDY WAS TO INVESTIGATE VARIATIONS IN THE DEFINITION OF CONTROL AREAS AS A FUNCTION OF TIME OF DAY SINCE THE VOLUME ON MANY OF THE LINKS VARIED SIGNIFICANTLY WITH TIME. AFTER SUBDIVISION OF THE NETWORK WAS ACCOMPLISHED AN ANALYSIS OF BENEFITS WAS CONDUCTED TO ESTABLISH THE VALIDITY OF THE DECOUPLING PROCESS. THE COUPLING INDEX ANALYSIS DESCRIBED HERE PROVIDES A SIMPLE STRAIGHTFORWARD TECHNIQUE BY WHICH TO IDENTIFY THE BOUNDARIES AT WHICH POTENTIALLY BENEFICIAL SUBDIVISION MAY BE ACCOMPLISHED.
ANALYTIC PROCEDURES FOR URBAN TRANSPORTATION ENERGY CONSERVATION: SUMMARY OF FINDINGS AND METHODOLOGIES. FINAL REPORT, VOLUME I
Analytical methodologies are described and illustrated for use by metropolitan planning organizations and other state and local transportation agencies in analyzing the energy conservation potential of candidate urban transportation measures. Quantitative methodologies oriented to carpooling, vanpooling, transit, pricing, traffic regulation and control, and auto ownership are provided based on the use of disaggregate behavioral travel demand models. Changes are indicated in trip frequency and distribution as well as in travel model, operating conditions, and vehicle miles of travel. Trip-based estimates of fuel consumption and vehicle emissions are included. The methodologies can be adapted to different levels and types of data availability, and can employ manual sketch planning procedures, a programmable calculator, or a fully-calibrated computer program utilizing a random sample household enumeration forecasting technique. Application of the developed methodologies has been performed in cooperation with metropolitan planning organizations representing the Dallas-Fort Worth, San Francisco, and Denver urban areas.