Gap Acceptance at Priority-Controlled Intersections

Abstract

Critical gap is the threshold by which drivers in the minor stream judge whether to accept a gap. If the gap is larger than critical gap, drivers accept it and enter the intersection; otherwise, drivers reject the gap and wait for the next gap. At a priority-controlled intersection, critical gap is usually considered as a fixed value or to follow a certain distribution. The major stream and minor stream are both one-way traffic flows at the priority-controlled intersection. Vehicles in the major stream have priority to run into conflict sections, and vehicles in the minor stream can enter conflict sections during the larger gap of two successive vehicles in the major stream. The capacity of minor roads is the maximum number of vehicles that can pass the intersection during a special period under prevailing roadway, traffic, and control conditions. Under a few assumptions, the survey method of rejected gaps and accepted gaps was designed. Four new calculation models of the critical gap are proposed. The probability function of rejected gap and accepted gap can be deduced by exponential rejected proportion function. Some important relations among variables of these functions can be obtained. The typical capacity functions were improved in terms of accepted proportion function.