Design Criteria for Crosswalk Width and Position at Signalized Intersections

Existing optimization methodologies for intersection operations assumes a fixed geometric design; however to produce the best performance, the geometry and operational system should be optimized simultaneously. Crosswalks at signalized intersections are complex and critical pedestrian facilities. Their geometry and configuration directly affect the safety, cycle length and resulting delays for all users. As crosswalks become wider or they are placed further upstream, the cycle length will increase due to the all-red time requirement, which deteriorates the overall mobility levels of signalized intersections. In contrast, when crosswalk width decreases, the required minimum pedestrian crossing time increases due to the bi-directional pedestrian flow effects, which leads to longer cycle length. Furthermore, existing manuals and guidelines do not offer any specification for the required crosswalk width under various pedestrian demand conditions. This study aims to develop new criteria for designing crosswalk width at signalized intersections, which can optimize the performance of signalized intersections from the viewpoint of vehicular traffic and pedestrians. The proposed methodology considers pedestrian demand and its characteristics, vehicle demand and the geometric characteristics of the intersection. The concept of optimized crosswalk width is proposed and demonstrated through a case study. Moreover, a comprehensive discussion regarding the existing strategies on positioning crosswalks is presented. The merits and drawbacks of each pattern are discussed. A previously developed methodology for modeling pedestrian flow at signalized crosswalks is utilized to estimate crossing time requirements and the reduction in crossing speed due to the bi-directional flow effects. It was found that at signalized intersections, which are characterized by low pedestrian and high vehicle demands, crosswalk width of 2 meters is appropriate to minimize cycle length and resulting delays for all users including pedestrians.