This paper describes a traffic conflicts computer simulation model and graphic display for both T and 4-leg unsignalized intersections. The goal of the model is to study traffic conflicts as critical-event traffic situations and the effect of driver and traffic parameters on the occurrence of conflicts. The analysis extends conventional gap acceptance criteria to describe driver's behaviour at unsignalized intersections by combining some aspects of gap acceptance criteria and the effect of several parameters including driver's characteristics such as age, sex, and waiting time. The effect of different traffic parameters such as volume and speed on the number and severity of traffic conflicts is also investigated. The model is unique insofar as it uses a technique of importance sampling and stores the traffic conflicts that occur during the simulation for later study. A graphical animation display is used to show how these conflicts occurred and the values of critical variables at the time. Model results were evaluated against previous work in the literature and validated by using field observations from four unsignalized intersections. The simulation results correlated reasonably well with actual conflict observations and should prove useful for assessing safety performance and feasible solutions for other unsignalized intersections. (A)
Samenvatting