A system to determine advisory speed limits for horizontal curves based on mental workload and available sight distance

Abstract

This study proposes a framework that accounts for mental workload and available sight distances to estimate advisory speed limits on horizontal curves. To achieve this goal, automated scripts were used to extract data on horizontal curve elements (i.e., the degree of curvature and the deflection angle), to detect crest vertical curves, and to compute the available sight distance from remote sensing data collected on highways in Alberta, Canada. Mental workload ratings were then assigned to each horizontal curve to calculate the perception–reaction time needed by drivers to maintain control of their vehicles while negotiating these curves. Finally, a curve advisory speed was calculated based on the available sight distance and the mental workload perception–reaction time needed to ensure a safe driving environment. This study presents a unique approach that incorporates human factors, including the responses of drivers based on their perception of the driving environment, in the development of speed advisory systems.