Critical Gap Distribution Estimation for Different Types of Vehicles in Rajshahi City, Bangladesh

Abstract

An essential factor that influences delay in unsignalized intersections critical gap between delay and capacity. Drivers’ critical gaps vary depending on the geometrical characteristics and the level of traffic. This study was conducted in Rajshahi city which is considered as one of the major important metropolitan cities of Bangladesh. Rajshahi City Corporation is the most center of urban, commercial, and educational activities of northern part of Bangladesh, which is now facing challenges with growing number of vehicles. Sagorpara bot-tola is one of the busiest intersections with a large number of different types of vehicles. For critical gap estimation, a total of 659 data was collected for three types of vehicles 2- wheelers (motorized & non-motorized), 3- wheelers (auto rickshaw, CNG, Mahindra, etc.), and 4- wheelers (car, truck, mini-truck, etc.). This city is now in alarming condition with 2 and 3 wheelers private and shared vehicles. In intersection, at peak period traffic congestion is now common picture because of less capacity to support large amount of traffic. It is also the cause of trip delay. It has a direct impact on our economic growth by wasting working hours. The objectives of this study determine vehicles critical gaps under complex traffic situations by using the Maximum Likelihood method. The model determined that the critical gap for drivers of cars was in the range of 6.97 and 4.29 seconds; for drivers of 2-wheelers, it was in the range of 6.73 and 4.4 seconds and for drivers of 3-wheelers, the values were in the range of 6.73 and 4.4 seconds. The proposed method's results at an uncontrolled intersection were shown to help identify 2- wheelers from 2- wheelers and 3- wheelers vehicles.