The Effect of Crosswalks on Traffic Flow

Abstract

In urban areas and especially in inner cities, pedestrians crossing the road considerably influence the road traffic flow. For political reasons, priority could be given to pedestrians. A larger number of crossings reduces the pedestrian load per crossing and facilitates both the pedestrian flow and the car flow; the ultimate case is a “cross anywhere” scenario. Earlier work shows that the road capacity decreases with the square of the pedestrian crossing time, hence a short crossing time is desired. Crosswalks can ensure pedestrians cross orthogonally, and thus quickly, and can thereby improve traffic flow. Moreover, a limited number of crosswalks is less stressful than a “cross anywhere” scenario for a car driver since (s)he only needs to expect crossing pedestrians at dedicated crosswalks. This paper studies the effect of the distances between crosswalk and road traffic capacity. The paper’s goal is finding a single formula or universal set of charts that can describe the effect of pedestrian crosswalks on traffic flow under virtually all scenarios (with long blocks). This type of result would obviate the need for simulations of specific situations when only a rough assessment of the effect of crosswalks is desired. Traffic flow for several distances between pedestrian crossings is simulated, and moreover, a non-constant inter-crosswalk spacing is considered. The simulation results can be used for other situations, using transformations and an interpolation recipe. Overall, the closer the crosswalks, the better the flow. However, spacings closer than approximately 25-50 meters do not add much. Speed of traffic under a broad array of pedestrian crossing scenarios is given.