Modeling Conflicts of Heterogeneous Traffic at Urban Uncontrolled Intersections

Abstract

The behavior of traffic in the heterogeneous environment of an urban uncontrolled intersection is complex and difficult to model. The present study describes the methodology of simulating the traffic flow and thereby estimating the number of conflicts in varying traffic flow conditions. The arrival pattern of vehicles was represented by a multivariate distribution to generate input to the simulation model. The model was validated externally, using field observed data, and was found to predict the number of conflicts well. As an illustration of usefulness of the model, variation of conflict rate (the probability of a vehicle's getting involved in conflict) due to variation in traffic volume and the proportion of right-turning traffic has been quantified. Under the prevailing traffic composition and turning movements, the conflict rate is estimated to lie in the range of 0.66–0.70, 0.79–0.84, and 0.80–0.87 for intersection volumes of 2,000, 2,500, and 3,000 vehicles per hour, respectively. Issues related to the applicability of the proposed model are briefly discussed.