Safety performance evaluation of highway intersection based upon traffic flow theories

The unique characteristics of highway intersections have caused them to be the most dangerous places in the road system. Complexity of causes of traffic crashes at highway intersections, difficulty in data collection of traffic accidents and traffic conflicts and many other reasons have made safety performance evaluation of highway intersections one of the most difficult tasks, in spite of the fact that studies on it have been carried out for quite a long time. Popular methods which are based upon traffic accidents and traffic conflicts are proved to be effective in certain circumstances, but difficulty in data collection of traffic crashes and subjective judgment and determination of traffic conflicts constrain their applications. Supported by the National Natural Science Foundation of China, this paper aims to set up a new approach to safety performance evaluation of highway intersections by application of traffic flow theories. Based on systematic analysis of causes of traffic accidents at highway intersections, the safety performance evaluation models take the form of possibility estimation of serious traffic conflicts. The models are efficient though their mathematical expressions are simple. By analysis of the models, some meaningful conclusions are drawn toward improvement of safety performance of highway intersection.