A THEORETICAL OVERVIEW OF ROAD HUMP EFFECTS ON TRAFFIC SPEED IN RESIDENTIAL ENVIRONMENTS <s> Research Gaps from Previous Literature <s> In its most simple terms, traffic calming is about preserving the functions of local streets. As local streets are intended to provide primarily land-access services, hence, when traffic begins to use local streets for through movements, traffic volume and speed levels become incompatible with this primary function. To respond, a study on the effectiveness of traffic calming measures in reducing vehicles speed at Taman Setapak residential area was undertaken. Field observations and spot speed survey were conducted to collect primary data. The field observation was carried out to collect data on road geometrics and design characteristics of the road humps. The spot speed survey was administered to collect vehicles speed at different points near the road humps. The major findings include first, the road humps proved effective in reducing the speed of the vehicles and second the design characteristics of the road humps is an important factor in reducing the speed of the vehicles. The average speed of the vehicles before approaching the road humps was about 30 km/hr and at the road humps below 10 km/hr. The findings showed that the design profiles of the road humps have an impact on the speed of the vehicles; the gentle the design profiles of the road humps especially in terms of its height and slope, the higher the speed of the vehicles near and at the road hump. The findings also showed a clear difference in the average speed of the motorcars approaching the road hump and at the road hump. <s> BIB001 </s> A THEORETICAL OVERVIEW OF ROAD HUMP EFFECTS ON TRAFFIC SPEED IN RESIDENTIAL ENVIRONMENTS <s> Research Gaps from Previous Literature <s> Speed humps are designed to ensure the safety of both drivers and pedestrians. The use of speed humps on residential streets is an efficient way of controlling the speed of vehicles traveling on them. Based on observations made in a case study, different geometric combinations of speed humps are currently in use. Although there are a few guidelines that stipulate specific ranges of dimensions for the installation of speed humps, no perfect or ideal guidelines have been introduced and properly enforced by the local authorities. Therefore, because there are so many styles and inconsistent designs of the speed humps, a well-established empirical study has been implemented to develop the optimal designs of consistency models. In this study, the 85th-percentile speed reduction and discomfort level were related to the geometric design of the speed hump. The speed data were obtained by using a laser gun meter detector to attain the spot speed data at the selected speed hump location, while the vibration data collection were obtained using the triaxial acceleration transducers connected to Racelogic VBOX II SX. Multiple linear regression analyses were conducted to develop a statistical relationship between the variables. Two models were successfully developed and validated according to the statistical procedures in the study. These models can be used as a basis for the design of speed hump geometry for a selected 85th-percentile speed reduction and discomfort level. <s> BIB002
The previous researches discussed on the effects of road hump profile and spacing was mostly limited to field tests and simulation studies. More studies should discuss field results together with general public understanding and perceptions on traffic calming, particularly in Malaysia. This is important given the inconsistencies in road hump installations throughout Malaysian urban residential areas, which may cause variations in driver behaviour and thus impact their speed selections. Variations in public opinion regarding hump effectiveness may also occur according to the device characteristics. In addition, the research conducted by BIB001 and BIB002 did not actively take into account the effect of other road humps or traffic calming devices in the same scheme as those studied, while Sundo and Diaz's (2011) study did not take the effects of the road geometry into consideration. In regards to the public perceptions briefly discussed above, a limitation of Cottrell et al.'s (2006) study was that the origins of all returned questionnaires were not recorded. Thus it was not possible to analyse the responses according to the neighbourhood or hump characteristics.