Transverse rumble strips thickness design for road users’ comfort

Transverse rumble strips (TRS) have been used as a common approach by road planners to enhance road traffic safety. It functions to reduce vehicle speed and increase the drivers’ alertness by generating vibration and sound effects to the vehicles. However, while TRS vibration is necessary to alert drivers, it may also become an issue when it is inappropriately designed as it generates excessive vibration that could affect road users’ comfort. This paper aimed to evaluate how TRS thickness and vehicle speed influence the vibration level and subsequently come up with an appropriate design of the thickness that could generate noticeable vibration to drivers but not too much in which can affect their comfort. In-cabin vibration measurement in the acceleration root-mean-square value, RMS (m/s2) was recorded while a test car was moving on the TRS samples with various thickness measurements on an actual road. The findings from a previous study on estimating the drivers’ vibration difference threshold by using Weber’s Law were used to estimate the appropriate TRS vibration and then the TRS thickness. The results indicated that vehicle speed and TRS thickness are highly significant to determine the TRS vibration. The recommendation for TRS thickness design for different average speed was proposed at the end of this paper.