Increasing Road Safety by Influencing Drivers’ Speed Choice with Sound and Vibration

Abstract

This paper discusses road safety issues and the necessity for safety enhancements, especially on rural roads. Points of discontinuity in infrastructure consistently lead to serious accidents. The major causes of these accidents are inattentiveness and excessive speed. A possible measure to increase attention and reduce speed is installation of transversal rumble strips (TRS). The German government funded a research project to evaluate the use of these strips in the approaches to hazardous bends. The design of rumble strips was optimized on the basis of literature research and metrological preexaminations. The resulting design is expected to create a maximal impact on the driver. The effect of these optimized rumble strips on speed choice was tested by field studies. In the approaches to hazardous bends on rural roads, rumble strips were installed according to the design of the pretests. The impact on the drivers’ behavior, especially on speed choice, was investigated by before-and-after analyses with radar measurements and video surveying. In addition to statistical analyses of the effect on the driving speed, detailed investigations on the impact to special driver groups and car types were performed. According to the analysis made in this research project, TRS are cost-efficient and have a positive effect on driving behavior and hence on road safety.

Operational Effects of Transverse Rumble Strips on Approaches to High-Speed Intersections

“…Therefore, the increase in sound level was sufficient to alert drivers that they were approaching the intersection. The average rise in acceleration rate (0.68 m/s 2 ) was less than the 2.5 m/s 2 to 4.25 m/s 2 change in previous studies (2,19). The average thickness of 0.16 in.…”

“…Tests by Walton and Meyer revealed that an average increase in sound from transverse rumble strips was 10 dB for cars and 4 dB for dump trucks (16). A study by Lank and Steinauer found the A-weighted volume in the area of the transverse rumble strips is on average 10 dB(A) above the basic noise level without transverse rumble strips (2). Horowitz and Nothbohm also measured the sound and vibration level generated by permanent cut-in-pavement (CIP) rumble strips and adhesive rumble strips (17).…”

“…Transverse rumble strips are a type of warning system that provides motorists with audible, visual, and tactile signals when approaching a decision point. In several countries, transverse rumble strips have been successfully used along approaches to points of discontinuity to affect driver behavior (1)(2)(3). In the United States, transverse rumble strips are mainly installed on approaches to intersections, toll plazas, horizontal curves, and work zones (4).…”

Design and preliminary testing of demand-responsive transverse rumble strips

“…One study concluded that the effectiveness of haptic signals depended on the suddenness of vertical deflection. 8 With increased familiarity and awareness of TRS location, the suddenness and thus effectiveness are reduced. In addition, exposure to TRS has been found to cause erratic maneuvers (e.g.…”

“…24 Nonetheless, any depth greater than 0.6 in was not effective in operations. 8 The current study developed a prototype of DRTRS with appropriate dimensions to cause both sufficient in-vehicle noise and vibration to regain the attention of the drivers and be mostly congruent with jurisdictional practice as well. The design and dimensions of DRTRS are discussed in detail in the ''DRTRS design methodology'' section.…”