Advanced Methods for Critical Gap Estimation in Mixed Traffic at Unsignalized Junctions

Abstract

An engineering concept known as the critical gap is frequently used to estimate the capacity of individual movements at unsignalized junctions. The majority of studies on critical gap estimation are based on homogeneous traffic situations where the rules of priority and lane discipline are actually followed. Driver behaviour and vehicle interactions at unsignalized junctions in mixed traffic patterns are intricate. Two T-intersections in the southern region of India are used in this work to estimate the critical gap using some of the known approaches, including lag, Harder, logit, probit, modified Raff and Hewitt methods. The findings demonstrate that critical gap estimates have values as low as 1.60 s and that there is a considerable difference (12%–38%) between values calculated using various methodologies. This demonstrates how the current approaches are unable to handle the mixed traffic scenarios. A different method of critical gap estimate is suggested that makes use of vehicle clearing behaviour along with gap acceptance data.