. . Rumble strips are raised or grooved patterns in a road’s shoulder designed to alert drivers with noise and vibrations that they are drifting off the roadway. They can be an effective safety measure to prevent run‐off‐the‐road (ROR) crashes, especially on limited‐access highways and rural two‐lane highways with long straight sections.(Rumble strips placed on the centerline can help prevent head‐on crashes.)
How do rumble strips impact cyclists?
. . Rumble strips are virtually impossible to ride a bicycle on or over– they are at best uncomfortable, even for a very short distance, and at worst can cause a cyclist to lose control of their bike and fall. They can damage a bicycle wheel, can cause a flat tire, and/or shake lose parts off a bicycle. Consequently, cyclists will avoid riding over themii – and when rumble strips leave no room on a shoulder, the cyclist will have no other option than to ride in the travel lane. While rumble strips do not deter car, truck or bus travel, they have a severe impact on bicycling travel, and have ruined popular cycling routes.
. . The negative impact of rumble strips on the ride‐ability of a roadway has prompted American Association of State Highway and Transportation Officials (AASHTO) and the Federal Highway Administration (FHWA) to provide guidance to follow when considering rumble strips on roadways used by cyclists. They recommend that rumble strips should not be used indiscriminately on roadways that are not limited‐access. Rumble strips should be used where there is a history of run‐off‐the‐road crashes; especially where there is sufficient recovery room for a motorist to react to the alert provided by the rumble strip; and when the impact cyclists can be minimized. This means that at least four feet of unobstructed roadway shoulder remains after the rumble strips have been installed.
. . States should train and monitor contractors to ensure best practices are followed. Advocates should work with their state DOTs, Municipal Planning Organizations (MPOs), and county road commissions to verify that unnecessary rumble strips are not installed and that preferred bicycling routes, especially, are kept free of rumble strips. It is important to get it right the first time. Improperly installed rumble strips are expensive to repair – often costing many times more than the original installation – and usually cannot be repaired without leaving behind an uneven surface or a shoulder prone to early failure.
Specific Elements to Address
. . 1. Too wide – many rumble strips are excessively wide, removing limited space on the shoulder for bicyclists to travel.
. . 2. Too deep – most rumble strips are ground‐in to depths that are excessive and dramatically more dangerous for cyclists.
. . 3. Continuous – rumble strips without gaps in the strip do not allow a safe way for cyclists to cross, merge or turn without hitting rumble strips.
. . 4. Placement – the lateral placement in a shoulder can make a shoulder that was once very comfortable to a bicyclist unusable.
More on Rumble Strips continues via the League of American Bicyclists at:
Lots more information on Rumble Strips in Tennessee can be found at the Bike Walk TN website at: