Temporal and Spatial Gap Acceptance for Minor Road at Uncontrolled Intersections in India

Capacity analysis of unsignalized intersections is done primarily with gap acceptance principles. The vehicles on lower-priority approaches maneuver when a suitable gap is available in higher-priority conflicting streams. Although temporal gaps are widely used, some researchers advocate the use of spatial gaps. The focus of this study was on analyzing temporal and spatial gaps at four-legged, partially controlled intersections in India. Unlike in developed countries, unsignalized intersections in India are not controlled with stop and yield signs with explicit priorities. The priorities are mainly set by the situations drivers perceive. Field data were collected at three four-legged intersections with video cameras. Temporal and spatial critical gaps were estimated with Raff's, logit, lag, Ashworth's, and maximum likelihood methods. The values of temporal critical gap by different methods were found to vary between 3.0 and 3.9 s. The spatial critical gap values varied from 29 to 36 m. These values were smaller than the similar values reported in developed countries, indicating aggressiveness in Indian drivers. The insights from this study can be used for the capacity analysis of unsignalized intersections in India.