Modelling of Driver’s Gap Acceptance for Evaluation of Traffic Flow Characteristics at Unsignalized Intersection in Urban Area, Ethiopia

Abstract

Introduction: Studying microscopic traffic flow characteristics has vital role in reduction of traffic problems. Gap acceptance and waiting time are traffic characteristics that are used in capacity, delay and level of service at unsignalized intersection. A lot of studies related to gap acceptance and waiting time has been done in developed countries under homogeneous traffic and road conditions. Objectives: This study is aimed to insight gap acceptance and waiting time behavior of merging or crossing vehicles in urban intersection under heterogeneous traffic condition and weak lane discipline in developing country like Ethiopia. Methods: In this paper three unsignalized intersection in Adama city has been selected on the basis of traffic volume and importance of the intersection. The primary data that were used for this study were traffic volume, speed, headway, waiting time, geometry of road, gap accepted and rejected. By using digital Camera, videos data were recorded; later quantitative data were extracted from videos. Two Statistical Packages that were used in analysis of this study. Minitab 19 was used for developing regression models of waiting time and gap acceptance for two maneuver types namely traffic turning to left and turning right from minor road. Result: Dichotomous generalized linear regression model (logit model) has been used to predict gap acceptance probability and validated by Hosmer-Lemeshow testing techniques to identify the goodness of model. The waiting time of drivers to accept and reject available gaps for three selected intersections were about 26sec, 24sec and 20sec. From the developed nonlinear model traffic turning to left moving with average speed 30kmph, average headway of 10sec and minor road traffic volume 2000PCu/Hr, increasing 25% major road traffic volume makes to double waiting time on minor road. Increasing major road traffic volume by 50% makes to quadruple waiting time.