New Concept Design of Directional Rumble Strips for Deterring Wrong-Way Freeway Entries

Abstract

Drivers who make wrong-way entries onto freeways pose a serious risk to the safety of other motorists and themselves. As a new countermeasure to mitigate the wrong-way entry issue, directional rumble strips (DRSs) were designed to generate elevated noises and vibrations to warn against wrong-way drivers and a normal level of stimuli to slow down right-way traffic. Five conceptual designs were developed based on Department of Transportation (DOT) guidelines, existing transverse rumble strips implementations, and input from rumble strip vendors. A national survey and extensive field tests were performed to verify the effectiveness of the proposed configurations. Acoustic and tactile signatures of the DRSs were measured by a specially equipped passenger car under different speed categories. The results indicated that the tested patterns could provide similar sound and vibration levels in the wrong-way direction as the existing transverse rumble strips (61.8–80.0 dBA sound signals and 1.1–1.4 g vibrations). The statistical and comparative analyses identified three DRS configurations that could produce greater audible and tactile signals in the wrong-way direction than the right-way direction, thereby serving the purpose of alerting inattentive wrong-way drivers while offering good visual attentiveness and applicability.