Studies have shown that rumble strips installed on a roadway significantly reduce the number of accidents caused by lane departures. However, when a vehicle engages the strips, a loud exterior noise is generated in addition to the alerting in-cabin noise. The extraneous exterior noise can travel at least several hundred feet at a volume which is considered a nuisance by nearby residents. In the recent years, a new rumble strip design in the form of a sine wave has been reported to produce low exterior noise, while still providing adequate warnings for drivers.

This study evaluated three sinusoidal rumble strips of different wavelengths—12, 18, and 24 inch. The rumble strips were quantitatively compared by measuring the noise inside and outside of the vehicle as well as the vibration of the front seat frame. Results showed that the sound responses varied across the vehicles. From the exterior, all three sinusoidal rumble strips were quieter than the traditional rumble strips, with a reduction in sound power by 5 to 11 dBA. Interior cabin sound level was similar to standard rumble strips, with some cases increasing between 2 and 9 dBA. The retro reflectivity tests also exceed the minimum threshold set by INDOT specifications.

Sinusoidal rumbles strips are a promising technology that is well suited for lane departure warning in residential areas. The results from this study suggest that the 12 in wavelength has a desirable decrease in exterior noise while still maintaining adequate lane departure warning to the driver.

Report Number



sinusoidal, rumble strips, safety, sound level, retro relectivity, vibration

SPR Number


Performing Organization

Joint Transportation Research Program

Publisher Place

West Lafayette, Indiana

Date of this Version