The road traffic systems, travel patterns and other traffic characteristics are different for each country due to differences in geometric patterns of a country, available transport facilities for commuters, rate of development in the transport sector and so on. Consequently, many standard relations and factors used in one region may not be suited for others. Therefore, an issue comes up to determine the different traffic engineering parameters which are appropriate to local urban transport system characteristics. One such endeavor is to determine the passenger car equivalent (PCE) at signalized intersections for the Dhaka Metropolitan City in Bangladesh where traffic characteristics are completely different from any other cities of the world. PCE currently used in Bangladesh is based on the values given in Geometric Design of Highways (MoC, 2001), which is the modification of the values given by Webster (1958) on the study performed in the United Kingdom in the 50sand 60s. But now-a-days, the situation is far different both for traffic and road user as the characteristics have changed from that time. Hence, in this paper an empirical study was carried out to determine the PCE of different types of vehicle that reflect the actual traffic conditions of Dhaka Metropolitan City. Data were collected from ten signalized intersections and the headway ratio method was used to estimate the PCE of different types of vehicle. The main vehicle compositions observed during the study period consist of passenger cars, auto-rickshaws, mini-buses and buses. The PCE obtained in this study were compared to the values established earlier. It was found that the_estimated PCE are smaller than those being used in Bangladesh.
Abstract