Microsimulation study of effect of volume and road width on PCU of vehicles under heterogeneous traffic

The traffic volume and roadway capacity are the important basic inputs required for planning, analysis, and operation of roadway systems. Expressing traffic volume as number of vehicles passing a given section of road or traffic lane per unit time will be inappropriate when several types of vehicles with widely varying static and dynamic characteristics are comprised in the traffic. The problem of measuring volume of such heterogeneous traffic has been addressed by converting different types of vehicles into equivalent passenger cars and expressing the volume in terms of passenger car unit (PCU) per hour. The vehicles of highly heterogeneous traffic such as the one prevailing on Indian roads may occupy any convenient lateral position on the road, based on the availability of space, without any lane discipline. This study is concerned with the estimation of PCU values of vehicles in such traffic conditions, using microscopic simulation. The PCU values obtained for different types of vehicles, for a wide range of traffic volume and roadway conditions, indicate that the PCU value of a vehicle significantly changes with change in traffic volume and width of roadway. © 2010 ASCE.