Learn about how we use rumble strips to keep vehicles on the roadway and reduce the frequency of collisions.
Rumble strips are an effective countermeasure to keep vehicles on the roadway and reduce the frequency of crashes. Drivers are alerted by the noise and vibration within the vehicle cabin caused by the uneven rumble strip surface.
Rumble strips & their use
Rumble strips are a pattern of depressions installed on the highway centerline or shoulder where an errant vehicle is expected to travel over them. Rumble strips alert drowsy or inattentive drivers that they have veered from their intended travel path. When a vehicle’s tires roll over the depressions, rumble strips transmit noise and vibration through the car, thereby alerting the driver that the car is departing from the travel lane.
In Washington, we usually mill rumble strips into the roadway surface. They are installed on the centerline, on the shoulder outside the edge stripe (fog line), or in both locations. The installation of centerline and shoulder rumble strips depends on roadway geometrics, lane and shoulder widths, and rural versus urban areas, with particular consideration given to expected roadway users.