Passenger Car Equivalents for the Heterogeneous Traffic on Divided Rural Highways Based on Simulation Model

Passenger car equivalent (PCE) values are necessary for representing a traffic stream composing of different vehicle types in terms of a passenger car equivalent stream. For no lane-based heterogeneous traffic streams observed in India, previous studies mostly have suggested the vehicle-specific PCE values that vary dynamically with the flow rate and the traffic composition. The objective of this paper is to estimate and analyze the implications of the vehicle-specific PCE values that do not vary with the LOS and certain range of traffic composition, for the four-lane and the six-lane divided rural roads. Besides, the present study has also estimated the aggregate PCEs for the four-lane and the six-lane divided roads. The PCE values were estimated based on the macroscopic relationships generated for the base and the heterogeneous traffic streams. For defining the level of service, a new performance measure termed as the speed drop was chosen and it was found that it provides a relatively more accurate PCEs. Results show that for a particular traffic mix, constant PCEs can be used across different levels of service without much loss of accuracy. Aggregate PCEs for a particular traffic mix vary with the speed drop markedly at lower flow rates.