Evaluation of presorted and presignaled intersections with respect to traffic efficiency and traffic safety

At many intersections, turning drivers have to yield to traffic from the opposite direction and crossing pedestrians and cyclists. Still quite limited understanding of the situation makes this task very demanding for autonomous vehicles. These can be segregated from the flow by means of presignals and be provided with exclusive protected movements. Signal control manages this “presorting and presignaling” system to adapt to the demand. Those changes potentially influence traffic safety and traffic efficiency at intersections and should be evaluated before implementing the system. In a microscopic traffic simulation study, “presorting and presignaling” is applied to a range of existing German intersections. The model is calibrated using headway and traffic conflict data. Different scenarios are created by varying traffic demand, signaling aspects, the share of autonomous vehicles and their driving strategies, both for the unchanged and the presignaled intersection. Firstly, the capacity and the level of service are estimated. Secondly, advances in traffic safety are examined using conflict measures like time-to-collision and post-encroachment time. Results show that typical traffic demand can be served and a trend towards traffic safety can be observed.