This investigation focuses on the observation-reaction time of pedestrians at uncontrolled crossing locations such as where pedestrian routes cross a carriageway, and near institutional and commercial complexes, bus stops and uncontrolled junctions. It is intended to be of assistance in the analysis and geometric design of roads, pedestrian crossings, and operational features. The principles described may also apply to controlled crossings and pedestrian facilities in general. The concept embodies the measuring and recording of 'minimum required' values of observation-reaction time when the pedestrian is not pressured into possible hurried or incomplete observations due to the presence of vehicular traffic, but who otherwise completes the observations as quickly as possible. This differs from concepts of pedestrian 'delay' and 'gap acceptance' times measured under actual site conditions which may reflect hurried decisions, and the absence in sampling of pedestrians who may be deterred from crossing due to traffic or infrastructure-related concerns. The concept includes consideration of pedestrians' saccadic head movements, focusing and a reaction time up to the point of starting to walk across the carriageway. The Green Cross Code is adopted as a commonly understood, respectable, sequence of actions used to determine a minimum yet complete observation process. The study indicates that the 85th percentile total time to fully but expeditiously observe the Green Cross Code for a two-way carriageway can take up to nearly 4 seconds for a mature adult with no disability. Implications for sightline locations and distances, intervisiblity and differing categories of pedestrian are addressed briefly, together with suggestions for further investigations. (Author/publisher).
Abstract