A.A. Mamun, H.M.I. Mahmud, M. Afroz, Q.S. Hossain, S.M.S.U. Kaiser
At any signalized intersection approach, the presence of right-turning vehicles affects the saturation flow by influencing the flow of through vehicles. The saturation flow is influenced by the proportion and types of vehicles in the traffic stream. As a result, passenger car equivalents (PCE) of turning vehicles are assigned to various categories of vehicles so that saturation flow can be corrected to the common base of passenger car units per hour. This study aims at estimating the PCE values of different type of right-turning vehicles at signalized intersections that reflect the traffic conditions of Dhaka Metropolitan City, Bangladesh. Data were collected from exclusive right-turning lanes at fourteen signalized intersections and the headway ratio method was used to estimate the PCE values. In Bangladesh, vehicle types comprises of passenger car, motorcycle, auto-rickshaw, mini-bus, bus and truck. The main vehicle composition observed during the study period consists of passenger car, auto-rickshaw, mini-bus, bus and motorcycle. The PCE values obtained for passenger car, auto-rickshaw, mini-bus, bus and motorcycle is 1.04, 0.94, 1.54, 2.37 and 0.69, respectively. The PCE values obtained in this study were compared to the values established earlier. It was found that most of the cases the estimated PCE values are smaller than those being used in Bangladesh.
Keywords: Passenger Car Equivalent (PCE); right turning vehicle; signalized intersection; headway ratio method; saturation flow