Keeping the Rumble in the Strips

Rumble strips are effective because the noise and vibration produced alerts drivers that they have left the traveled way. As a result, it is important to keep rumble strips operating properly. While milled rumble strips typically do not require maintenance during the life of the pavement, raised rumble strips can be displaced by traffic and may periodically require replacement.

EFFECT OF RUMBLE STRIPS ON PAVEMENT LIFE

Maintenance crews were initially concerned that heavy traffic would cause shoulder pavements with rumble strips to crumble faster, or that the freeze-thaw cycle of water collecting in the grooves would crack the pavement. These worries have proved to be unfounded where rumble strips were in installed in pavements in fair to good condition. Rumble strips have little if any effect on the rate of deterioration of new pavements.

OVERLAYING RUMBLE STRIPS

There are various approaches to surface preparation when paving over existing rumble strips. Some agencies mill out the existing rumbles, inlay with new pavement, then overlay the entire roadway. Other agencies simply overlay new pavement over the existing rumble strips. Agencies have taken various approaches to re-installing rumble strips after paving operations. Some agencies re-install the rumble strips immediately, as part of the resurfacing project, while others chose to re-install the rumble strips during area-wide milling projects and replace rumbles on all recently paved projects. For more information, see Frequently Asked Questions

RUMBLE STRIPS AND SNOW PLOWING

Snow plow operators have indicated a positive effect of rumble strips – they associate the rumble strip pattern with their ability to discern the limits of their travel lane. When installed in durable pavement (whether new or existing), rumble strips are not affected by freeze/thaw cycles any more than the surrounding pavement. Even in snowy conditions, the rumble pattern is sometimes discernible and can improve driver recognition of the limits of their travel lane.

• Milled Rumble Strips: Weather appears to play no significant role in the durability of milled rumble strips. Field observations refute concerns about the effects of the freeze-thaw cycle as water collects in the grooves. These observations show that wind and the action of wheels passing over the rumble strips in fact knock debris, ice, and water out of the grooves. Ironically, snow plow drivers have come to depend on shoulder rumble strips to help them find the edge of the travel lane during heavy snow and other low visibility situations.
• Raised Rumble Strips: Snow plow blades passing over raised rumble strips tend to scrape raised rumble strips off the road surface. As a result, raised rumble strip use is usually restricted to areas that do not contend with snow removal.

RUMBLE STRIPS IN WORK ZONES

Shoulder rumble strips challenge maintenance and rehabilitation crews when lane closures require traffic to be diverted to the shoulder. For long-term rehabilitation projects on asphalt pavements, most road agencies simply fill in the rumble strips. Once construction is complete, the shoulder is resurfaced and new rumble strips are milled into the new asphalt overlay.

Other Considerations and Resources

• Rumble Strip Implementation Fact Sheet: Pavement. This fact sheet is intended to provide general information on this topic to anyone involved in a rumble strip project.
• Rumble Strip Implementation Guide: Addressing Pavement Issues on Two-Lane Roads This guide is intended for noise and safety professionals involved in the development of project-specific implementation of rumble strips or development of standards.
• FHWA Technical Advisory on Shoulder and Edge Line Rumble Strips (T 5040.39, Revision 1) 
• FHWA Technical Advisory on Center Line Rumble Strips (T 5040.40, Revision 1)