Sinusoidal Rumble Strips

Sinusoidal Rumble Strips are typically used in sound sensitive areas where traditional rumble strips have not been installed due to the unwanted noise caused by vehicles regularly drifting out of their lane. One exception includes metro locations where there are dedicated bus lanes where rumble strips are used even in urban areas.

For sound sensitive areas, sinusoidal rumble strips are a viable alternative. Sinusoidal rumble strips still capture the driver’s attention through in-vehicle-generated sound levels and vibrations but external noise levels are significantly reduced.

Rumble Strip Test Video

Sinusoidal Rumble Strips Research

A study by the California Department of Transportation (Caltrans), explains why sinusoidal rumble strips are so effective. Sinusoidal rumble strips reduce the exterior noise of the vehicle by fluctuating the distortion of the tire as it passes over the rumble strip. There are no abrupt changes in the profile of the pavement that tend to generate higher frequency exterior noises. 

Meanwhile, sound levels within the vehicle are similar to standard rumble strips, and in some cases higher, including the vibration of the steering column. The lack of abrupt changes to the pavement profile also makes sinusoidal rumble strips more bicycle friendly than traditional rumble strips! 

Sound is measured in decibels on a logarithmic scale, so for every 3 decibels you move down the scale, you are dropping 50% of your remaining sound. Table 1 shows how the change in decibels is measured. Because sinusoidal rumble strips can reduce exterior noise from between 3 to 14 decibels the results can be drastic (50-90% noise reduction).