Development of Passenger Car Unit (PCU) for Streets in Erbil City

Passenger car units (PCU)s are used to represent the effects of varying mixed vehicle types on traffic stream. Traffic volume data is very important to design, planning and analysis of traffic roadways system. PCU of different types of vehicles offer different degrees of interference to other traffic stream. It is necessary to bring all types of vehicles to a common unit. The common unit adopted for expressing the volume as PCU per hour. In this paper, the required data was collected at five main urban roads in Erbil City using a digital video recorder technique. The aim of the study is to work on the PCU for different types of vehicles under mixed traffic conditions. It has been observed from the present study that the PCU values of vehicles significantly change with change in traffic volume and width of roadway. Statistical analysis of the results show that a PCU value for buses was found to be 2.92. The PCU value for buses in Erbil was found to be similar to that obtained in Iraq but different from UK and same idea about other types of vehicles. Also, the capacity of highways increases with the use of shoulder areas and it has a positive effect on PCU values for type of vehicle increase with increases lane widths. PCU values for Motorcycles, Tricycles, Cars and buses/trucks have been evaluated. The average (PCU) value of the Three different methods were used to determine the PCU. These methods are Headway, Density and Homogeneous Coefficient method, mentioned in detail differ by 0.3 in SORB, but It differing by 1 to 1.5 in HCM.