Influence of major stream composition on critical gap at two-way stop-controlled intersections - a case study

Gap acceptance method used in the analysis of two-way stop-controlled intersections is based on the assumption that major street traffic is uninterrupted. However, the present study found a clear difference among the traffic characteristics of the major street at the intersection and upstream of it. The distributions of inter-arrival times and speeds of major street vehicles are significantly modified as they approach the intersection. Data collected from five intersections in India were used to estimate the critical gaps for motorized two-wheelers and cars executing two non-priority movements (right turn from major and minor streets). Critical gap, estimated using occupancy time method, was found to vary among intersections, even when they were similar in geometry. This is attributed to the proportion of large-size vehicles in the conflicting traffic. A statistically strong relation is found between the critical gap of a vehicle type and the proportion of large-size vehicles in the conflicting traffic.