REVIEW ON PASSENGER CAR UNIT STUDIES IN HOMOGENEOUS AND HETEROGENEOUS TRAFFIC FLOW-A PERSPECTIVE

It is usually true that wise people get benefited in all the future endeavors, based on their learning's and accomplishment that were experienced in the past. In this paper many of the milestones in the development of Passenger Car Unit (PCU) are reviewed. An attempt has been made to cover the critical and the most current research work in the development of PCU in both homogeneous and nonhomogeneous traffic conditions, though the review is not exhaustive. Passenger Car Units or Passenger Car Equivalents (PCE) plays a vital role in studying the traffic flow of diverse vehicle types in the traffic stream and is used to transform traffic stream consisting of different vehicle types into traffic stream consisting of only passenger cars and they are worked out to analyze the relative effect of different type of vehicles on the road. The present paper reviews and compiles various methods that have been followed to estimate the value of PCUs. Each method has its own factors like density, headway, speed, delay etc. that are taken into account for calculation of PCU. In this context, present study also identifies the gaps in research areas which needs further work to be carried out in Indian traffic conditions.