Gap Acceptance at Atypical Stop-Controlled Intersections

Abstract

A gap acceptance study was performed at a T-intersection at which left-turn traffic on the through leg had the right-of-way. A number of methods were used to model the critical gap size at this atypical intersection. The critical lag and gap values varied according to the method used to compute them, and the different movement or conflict combinations exhibited different critical values. On the approach required to stop, representative values ranged from a 7.8-s critical gap with the higher priority traffic stream from the right, to a 2.2-s critical lag with the highest priority traffic from the opposite direction. The drivers involved in certain movement or conflict patterns at this intersection with the atypical right-of-way pattern were quite comfortable with short lags and gaps.