Using driving simulator to study the effect of crash fact signs on speeding behaviour along freeways.

A driving simulator study was utilized to evaluate a potential countermeasure for speeding behaviour in order to reduce speed spillover. The behaviour of 56 subjects was observed. Participants drove a freeway for 5300 metres before exiting onto a three-kilometre urban arterial. Field data from trajectory speed profiles validated the diving simulator results. The impact of the Crash Fact Sign (CFS), a sign that provides information about the number of crashes/fatalities that occurred on that particular road, and Warning Sign (W.S.) on regions affected by speed spillover was investigated. Each subject was asked to drive in four different scenarios: (1) an additional speed limit sign (SLS-2); (2) Warning Sign (W.S.); (3) Crash Fact Sign (CFS); and (4) Crash Fact Sign with Additional Speed Limit Sign (CFS&SLS-2). The study finds CFS&SLS-2 to be the most effective countermeasure because it produces significant average speed reductions, reached 7.8 km, in the area under speed spillover effect. Furthermore, the effect of a traffic signal at the exit urban arterial on speed spillover behaviour was investigated. The speed spillover effect was observed at longer distances when drivers did not stop at the signalized intersection than when drivers stopped.