A review of critical gap estimation approaches at uncontrolled intersection in case of heterogeneous traffic conditions

Abstract

The gap acceptance study is an indispensable study in the determination of capacity and delay of the individual moment at uncontrolled intersection and critical gap is one of the chief parameter allied with this study. Most of the studies related to critical gap estimation have been carried out in developed countries where traffic is homogeneous and rules of priorities as well as lane disciplines are voluntarily followed. However, in India, priority rules are less honored which consequently create more clashes on intersections and modelling of such behavior becomes complex. Even though very limited studies have been reported in such case. This paper presents the study of gap acceptance behavior of drivers on an uncontrolled intersection. In order to examine the gap acceptance behavior of drivers, 4-legged uncontrolled intersection located in a semi-urban area of Ahmedabad in the state of Gujarat was selected. Video recording technique was adopted for collection and analysis of the data. Different existing methods are used to calculate the critical gap for through and right turning movements from the minor road. Gaps are analyzed for three different vehicle types. A comparison between different existing methods of critical gap determination is carried out and their critical analysis is presented. The result shows, except clearing behavior approach, all other methods are failing to represent the actual scenario of the critical gap under mixed traffic conditions as these all methods had been developed for homogeneous traffic conditions.