Studying critical pedestrian behavioral changes for the safety assessment at signalized crosswalks

Abstract

Pedestrian-vehicle conflicts are one of the most important safety concerns at signalized intersections especially in urban areas. Conflicting vehicles and pedestrians select their maneuvers by predicting the other user behavior. Sudden behavioral changes of pedestrians such as sudden speed change (acceleration or deceleration) cannot be predicted by drivers, which can lead to safety hazards especially if these sudden behavioral changes occur near conflict areas. In this study, continuous pedestrian speed profiles were analyzed at signalized crosswalks to investigate the existence of such behavioral changes. A methodology is proposed to identify significant sudden changes of pedestrian speeds. The locations and timings of these sudden speed change events were analyzed, and the influencing factors such as crosswalk geometry and signal timing were studies and evaluated. Five signalized crosswalks at three intersections in Nagoya City were videotaped for analysis. Individual pedestrian maneuvers were extracted with image processing software. Empirical analysis showed that sudden acceleration events were observed at the entrance points to the pedestrian-vehicle conflict area, which highlights the significance of these events to pedestrian-vehicle conflict analysis. A multinomial logit model was developed to estimate the probability of a pedestrian making a sudden speed change as a function of different influencing factors. The results implied that the entering speed, necessary speed to finish crossing before the onset of the pedestrian signal red phase, and crosswalk length have a significant impact on speed change choices. This paper presents important suggestions to understanding pedestrian maneuvers in detail from the viewpoint of safety.