Prediction of the Operating Speed Profile Approaching and Departing Intersections

Abstract

The operating speed profile is a useful tool for diagnosing potential safety issues on existing highways and for alignment design. Unfortunately, existing operating speed profile prediction models do not take into account the presence of intersections along roads because a procedure to estimate a reliable operating speed profile on the road section along which driver speed behavior is affected by an intersection is not currently available. To overcome this limitation, driver speed behavior approaching and departing from at-grade intersections and modern roundabouts was studied and a procedure to predict the operating speed profile along a road section characterized by the presence of an intersection was developed. This simple procedure uses the same construction rules as the existing operating speed profile models in order to be easily integrated into them. The procedure developed predicts a reliable profile in the proximity of at-grade intersections and roundabouts along two-lane rural roads, thereby improving significantly the possibility of applying this useful tool to safety evaluations.