An Analysis of the Impact of Reducing Pedestrian-Walking-Speed on Intersection Traffic MOEs

Pedestrian traffic is an important element in signalized intersection analysis. As a low-speed traffic component, pedestrians crossing the street may take up time that could be utilized by vehicles on the other street to pass through the intersection, and this causes an increase in the total delay at the intersection. Therefore, to minimize traffic delays and increase traffic efficiency, it is important to study the impact of pedestrian walking speed.

This study was conducted to analyze the impacts of pedestrian speed under different lane group combinations, median widths, volumes on major and minor streets, and pedestrian pushbutton horizontal offsets. The idea originated came from the reduction of pedestrian walking speed used for calculating the pedestrian intervals. The 2003 MUTCD specified a value of 3.5 ft/sec to calculate the pedestrian clearance time and this speed was reduced to 4.0 ft/sec in the 2009 MUTCD. Moreover, a second method using 3.0 ft/sec to calculate the total pedestrian intervals was added to the 2009 MUTCD. This change is likely to influence the signal timing plan of entire intersections and further increasing the intersection total delay.

The researcher used one of the most popular simulation software programs, Synchro 7, to simulate various types of intersections under different traffic circumstances and yield a series of datasets to analyze the impacts of the reduction in pedestrian walking speed. The data was analyzed both horizontally and vertically. By comparing the intersection total delay as well as the through lane group and the approach average delay, the researcher analyzed their differences mathematically as well as practically. According to the analysis results, if the cycle length of an intersection can be optimized, the change of pedestrian walking speed would not make significant impact on intersection delay; however, if under a given cycle length other than its optimum one, the intersection delay would increase significantly after the change of pedestrian walking speed in some circumstance. The extended pushbutton press function can be used to alleviate such delay increase.