Modeling Automobile Interference due to Midblock Pedestrian Activity on Urban Street Segments

Abstract

The 2010 highway capacity manual (HCM) provides an approach to estimate the mutual between pedestrians and automobiles at signalized intersections. However, the manual provides little guidance for capturing the interactions between pedestrians and automobiles at unsignalized midblock pedestrian crosswalks on urban street segments. The movements of vehicles on urban streets can be significantly impacted by midblock delays and stops. One of the performance measures in evaluating automobile performance on urban street segments is the travel speed. The manual computes the segment travel speed based on the segment length, the segment running time, and the control delay. Friction conditions, such as the midblock pedestrian crossings, interfere with the traffic flow on urban street segments and therefore increase the segment running time, which consequently lowers the travel speed and the level of service (LOS) of the segment. The frequency of the interference to vehicles is related to the frequency of the arrival of pedestrians and the flow of vehicles. This paper develops and evaluates a model to estimate the frequency of midblock pedestrian interference to vehicles at unsignalized midblock crosswalks on urban street segments, using the traffic volume, the pedestrian volume, and the median type and posted speed limit as the independent variables. The results show that the traffic volume and the pedestrian volume are the most significant models.