In a mixed traffic situation, where different types of vehicles share the same roadway space without any physical segregation, the amount of interaction is expected to change with the mix characteristics. The interaction among the vehicles is greatest during peak period on urban roads. The common practice to analyse mixed traffic flow is to convert all vehicles into equivalent numbers of passenger car units (PCUs). A mathematical equation relating PCU for a vehicle type to the influencing variables is suggested in this paper. The variation of PCU with traffic and geometric variables is explained graphically. A computer program suitable for running on a personal computer is developed to estimate the PCU value for a vehicle type under given conditions of composition and traffic volume per lane width. (a).
Abstract