Operational and Geometrical Conditions of Accident Occurrence and Severity at Signalized Intersections

Abstract

This research investigated the effect of road geometric features and operational conditions on the occurrence and severity of traffic accidents at signalized intersections in Abu Dhabi city, UAE. Speed, number of lanes, lane configuration, traffic signal sequence (lead/lag or split phasing), average hourly traffic volume per lane were used as independent variables. The accident occurrence was tested by using Poisson’s regression modeling and the accident severity was examined by using multinomial logit modeling approaches. The Poisson model showed that at 4-leg intersections, one of the major causes of the accident, is passing of a street (either minor or major street) through the intersection. It was also found that at 3-leg intersection, the main cause of the accident is minor street passing through the intersection. The research also found that the higher the traffic volume the higher the chance of occurrence of traffic accidents. The multinomial logit model showed that five significant variables affect the severity of traffic accidents occurs at signalized intersections. the significant variables are the speed of the main road, traffic signal sequences, number of through lanes of minor road number of left lanes of main and minor roads.