Rumble Strips and Stripes

Frequently Asked Questions

Q: What is the basis for recommending shoulder rumble strips only where a clear 4-foot surface is provided beyond the rumble strip?

A: While we do recommend shoulder rumble strips where there is 4 feet or greater of shoulder beyond the strips, we do not recommend against rumbles where there is less than 4 feet. In those cases there are many issues for the responsible agency to consider, including whether it is used by bicyclists and therefore needs a specified amount of paved area beyond the rumble strip to accommodate them. Using the metric of 4-feet in the recommendation allows a practice that will work as a typical application, and accommodate cyclists.

Follow-on Q: Why does the guidance recommend that a 4-foot paved or unpaved should be provided? Bicyclists cannot use an unpaved shoulder.

A: The recommendation to install rumble strips on a road with an unpaved shoulder is not dependent on whether cyclists are able to use the shoulder, but rather on whether there is the potential to save lives by alerting drivers when they drift off the road. The unpaved shoulder provides a clear recovery area for the motorist. The cost for installation of the rumble strips in such a location is very low in comparison to providing a paved shoulder along with the rumble strips.

Q: Why doesn’t the guidance recommend a 4-foot shoulder wherever bicycle travel is legally allowed?

A: There is a bicycle accommodation policy for the US DOT. That policy, rather than this, should direct placement of bicycle facilities and bicycle accommodation. While we seek not to infringe on use by bicyclists as we install life-saving rumble strips and rumble stripes, we need to balance the safety of all users and consider including rumble strips where it can save lives while only causing a minor inconvenience to cyclists. One of the issues to consider is that by alerting motorist drifting from there lane, the rumble strips may save a cyclist’s life.

Q: Are rumble strips recommended for residential use?

A: Not typically. Noise is often an issue in residential areas, so other alternatives may be more appropriate. However, this is not always the case when there are residences along a highway in a rural area or on the edge of an urban area.

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Program Contact

Cathy Satterfield

708-283-3552

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