Estimation of PCE for Heterogeneous Traffic Stream in the Dual Carriageway Section

Abstract

AbstractPCE are used as the factors to transfigure a traffic stream which is composed of various class of vehicles into an equivalent traffic stream composed absolutely of passenger cars. Based on various parameters of traffic stream traffic speed, traffic density, traffic flow and traffic headways PCE values are calculated. Present study analyses that various methods have been used to forecast the PCE values. It is too tough to estimate the traffic volume and traffic capacity of carriageway under heterogeneous traffic conditions. So, to get a standard vehicular unit, PCE has been developed to compare the congestion caused by different vehicles. The PCE values as introduced by developed countries are inappropriate for Indian mixed traffic condition because traffic is more heterogeneous and miscellaneous in nature. HCM utilizes PCE factors to estimate the effect of heavy vehicles on traffic stream under mixed traffic conditions. Different vehicles have significantly various driving performance characteristics to that of passenger cars. Therefore, these vehicles can have a major impact on traffic operations. It is therefore important to account properly for this impact in the traffic stream analysis in order to reflect the functioning quality of carriageway as close as possible. The primary objective of the research is to determine the appropriate PCE values of different vehicles. Additionally, a general PCE value with only one vehicle category was developed for planning purposes. The development of PCE values were based on the relative headway concept. For analysis of PCE, a significant amount of field data was collected during both peak and off-peak hour for the purpose of calibration. The PCE values determined from this study were 4.57, 3.76, 2.13, 0.28, 0.53 and 1.38 for peak hour and 4.6, 3.63, 2.14, 0.29, 0.55 and 1.33 for off peak hour for truck, bus, LCV, 2-wheeler, cycle and 3-wheeler respectively.KeywordsCapacityPassenger car unitHeadwayHeterogeneous trafficTraffic stream