Citation

Prathapan P, Rajamma A. Int. J. Traffic Transp. Eng. (Belgrade) 2016; 6(4): 453-473.

Copyright

(Copyright © 2016, City Net Scientific Research Center, Faculty of Transport and Traffic Engineering, University of Belgrade)

DOI

10.7708/ijtte.2016.6(4).08

PMID

unavailable

Abstract

Estimation of saturation flow under heterogeneous traffic condition is a challenging task in the capacity analysis of signalised intersections due to complexity of vehicular interaction. Studies have established that quantification of vehicular interaction can be achieved by estimating Passenger Car Unit (PCU) values for different categories of vehicles in the traffic stream. Most of the studies have used ratio between speed differential and horizontal projected area of vehicles to model dynamic PCU. At signalised intersections speed ratio would not vary much and hence these models do not capture the exact dynamic nature of PCU in its full extent. In this study dynamic PCU for heterogeneous traffic at signalised intersections is estimated based on area occupancy, an indirect measure of extent of road usage. Traffic flow details at the intersection area during saturated green time are collected from different signalised intersections to determine the area occupancy of the heterogeneous traffic. The field determined area occupancy and mean occupancy time are utilized to determine the equivalent homogeneous traffic stream area and the number of standard car spaces (NCS) existing in the traffic stream. The individual PCU values are estimated based on NCS and number of various categories of vehicles existing in the traffic stream during saturated green time. The PCU values estimated indicate that traffic characteristics, control conditions and approach width have significant effect on PCU values and the effect is predominant in the PCU values for heavy vehicles. The PCU values of vehicles passing through signalised intersections with the control condition through and right turn movement permitted in same phase are lower than the PCU values of vehicles passing through intersections having through only movement in one phase.

Language: en