Edinburgh Napier University

  PCU (Passenger Car Unit) values are used in traffic management and transportation planning to calculate the flow volume in mixed traffic. However, the impact of motorcycles on road capacity is difficult to measure due to their ability to undertake both lane-based and non-lane-based movements. This study employed an agent-based simulation model to measure the flow volume of mixed traffic and estimated the PCUs of motorcycles in congested flow. The influences of several conditioning variables such as the number of lanes, the width of lanes, the proportion of motorcycles and the speeds of passenger cars are analyzed. The results indicate that the often used PCU value of 0.5 in transportation planning is inappropriate in some traffic conditions. This study suggested the PCUs of motorcycles in congested flow to be 0.40, 0.55 and 0.75 when the speeds of passenger cars are ranging from 10 to 20, 20 to 30, and 30 to 40 km/hr respectively.