Effectiveness of Shoulder Rumble Strips: A Survey of Current Practice

The New York State Department of Transportation recently adopted a policy and specifications for use of rumble strips or “audible roadway delineators” on shoulders to assist in preventing drift-off accidents. To verify the quality of this policy and specifications, transportation agencies in the United States and Canada were surveyed concerning current practice, and this report summarizes the responses. Rolled-in and milled-in delineators are used extensively in both countries, and both have advantages and disadvantages but are effective in preventing these accidents. Factors that must be considered when specifying these delineators include location, noise, safety of cyclists, shoulder condition and dimensions, and history or potential for drift-off accidents.