Effective Low Noise Rumble Strip Design and Performance

The purpose of the NCHRP 15-68 Effective Low Noise Rumble Strips project research was to develop and recommend a rumble strip design to achieve somewhat conflicting goals. The design was to minimize the exterior noise that can affect residences along a roadway while producing sufficient interior noise and vibration inside the vehicle to alert the operator of a lane departure. Review of the previous research indicated that this could best be accomplished with a rumble strip of a sinusoidal profile. The first portion of this research was to develop a recommended test procedure which was presented at the 2022 TRB Annual Winter Meeting. Using this procedure, sinusoidal strips were tested in three different states, which included four different wavelengths, 12, 14, 18, and 24 in. The smallest of these produced sufficient interior noise and vibration; however, it produced higher levels of pass-by noise. The largest of these produced the lowest pass-by levels but insufficient interior noise and vibration relative to existing criteria. To explore the intermediate dimensions, 20 different designs of sinusoidal rumble strips were constructed and tested in Washington State. In addition to wavelength, the peak-to-peak dimension of the sinusoidal shape, and the amount that the shape was recessed relative to the existing pavement surface were tested. From the results of the testing of strips, a wavelength of 14 to 15 in., a peak-to-peak amplitude of 7/16 in., and no recess are recommended.