Effect of Pedestrian-Related Factors on Intersection Performance

The Manual on Uniform Traffic Control Devices (MUTCD) contains the national standard for installing and maintaining traffic control devices on all streets and highways. The 2003 MUTCD contains numerous corrections, revisions, and updates to the millennium edition (2000). One update is related to the definition of crossing distance at signalized intersections, where the crossing distance is extended to the far-side curb rather than the center of the farthest traffic lane. This study investigated the sensitivity of intersection performance to crossing distance and walking speed, critical constraints in the determination of the minimum green time. Three crossing distance standards and four walking speeds are considered. With Highway Capacity Manual (HCM) procedures, the impacts of the given crossing distance definitions and walking speeds on intersection operations were tested on two intersection configurations over a range of cycle lengths and traffic volumes. The effect on intersection performance was found to be most significant at low cycle lengths, in some instances with the delay increased manyfold. However, when cycle lengths were increased to account for the pedestrian constraints, optimal delay rarely increased by more than a few seconds. Additionally, as the discrepancy between the critical lane traffic volume on the main and cross streets was increased, the impact of pedestrian green times on vehicle delay also increased. It was seen that as the cycle length increased, pedestrian minimum green times no longer governed, so the impact of pedestrians on intersection performance became increasingly insignificant, often with a minimal impact on the optimal performance.