Analysis of Critical Gap and Capacity at Skewed Uncontrolled Intersections

Abstract

Critical gaps and capacity of movements at uncontrolled intersections are influenced by intersection geometry, especially in mixed traffic conditions. However, existing models to compute the capacity of uncontrolled base intersections are only suitable for intersections with 00 to 100 skew angles. This study aims to bridge the gap by evaluating the effect of skew angle on the critical gap and capacity of uncontrolled intersections. The critical gap models are developed for different vehicle types. The capacity of uncontrolled intersections is determined for different skew angles (00 to 270) using simulation and Indo-HCM models. The comparison reveals that the Indo-HCM model over-predicts the capacities. Thus, new capacity models are proposed, and it is observed that the capacity varies as a quadratic function of the skew angle, where the constant indicates base capacity. This study also provides the adjustment factors for Indo-HCM capacity models to deduce the capacity of any skew-angled intersections.