Pedestrian crossing design and analysis for symmetric intersections: Efficiency and safety

Traffic engineers are making efforts to mitigate congestion and to improve efficiency at intersections. The symmetric intersection (SI) can increase the capacity of intersections and is economical, practical, efficient and convenient. The pedestrians' crossing patterns tailored for SI has not yet been studied. This paper not only develops three pedestrian crossing patterns but also analyzes crossing patterns from the aspects of efficiency and safety. For efficiency, delay models are proposed by considering through and diagonal pedestrian movements. For safety, exposure conflicts and the number of potential traffic accidents are analyzed. Then delay and potential accidents are converted into money value respectively and the total cost is calculated. The case study results show that SI performs better in terms of increasing capacity and decreasing pedestrian delay compared with conventional intersection. Crossing pattern 1 is efficient but unsafe while the total delay and safety cost of pattern 3 is usually the highest. The sensitivity analysis indicates that cycle length has a negative impact on average pedestrian cost and if critical flow ratio increases, the average pedestrian cost of pattern 1 and pattern 3 will increase and decrease respectively. Furthermore, the best pedestrian pattern choice under different values of cost per accident and cost of pedestrian delay is also studied.