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FHWA Home / Safety / Proven Safety Countermeasures / Proven Safety Countermeasures - Median Barriers

Proven Safety Countermeasures

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For more information about this Proven Safety Countermeasure, visit the Office of Safety's Safety EdgeSM website.

SafetyEdgeSM

FHWA treskelion logo.
U.S. Department of Transportation
Federal Highway Administration

FHWA-SA-17-062

Icon representing SafetyEdge.

SafetyEdgeSM

Example of SafetyEdge after backfill material settles or erodes.

Source: FHWA.

SAFETY BENEFIT:

11%
Reduction in fatal and injury crashes

Source: Safety Effects of the SafetyEdgeSM, FHWA-SA-17-044.

Cross-section view of an overlay with SafetyEdgeSM. Base layer is on the bottom, with old pavement and an old graded shoulder on top of the base. On top of that is new overlay with safety edge and a new graded shoulder, creating a 30 degree angle on the new shoulder.
Source: FHWA-SA-17-044

SafetyEdgeSM technology shapes the edge of the pavement at approximately 30 degrees from the pavement cross slope during the paving process. This systemic safety treatment eliminates the vertical drop-off at the pavement edge, allowing drifting vehicles to return to the pavement safely. It has minimal effect on asphalt pavement project cost with the potential to improve pavement life.

Vehicles may leave the roadway for various reasons, ranging from distracted driver errors to low visibility, or to the presence of an animal on the road. Exposed vertical pavement edges can cause vehicles to be unstable and prevent their safe return to the roadway. SafetyEdgeSM gives drivers the opportunity to return to the roadway while maintaining control of their vehicles.

For both SafetyEdgeSM and traditional edge, agencies should bring the adjacent shoulder or slope flush with the top of the pavement. Since over time the edge may become exposed due to settling, erosion, and tire wear, the gentle slope provided by SafetyEdgeSM is preferred versus the traditional vertical pavement edge.

Transportation agencies should develop standards for implementing SafetyEdgeSM on all new asphalt paving and resurfacing projects where curbs are not present, while encouraging standard application for concrete pavements.

The SafetyEdge adds nominal cost to repaving a road. Calculated benefit-cost ratios typically range between 500-1400. (Source: Safety Effects of the SafetyEdge.) Rural road crashes involving edge drop-offs are 2 to 4 times more likely to include a fatality than other crashes on similar roads. (Source: S.L. Hallmark, et al., Safety Impacts of Pavement Edge Drop-offs, (Washington, DC: AAA Foundation for Traffic Safety: 2006), p 93.)


For more information on this and other FHWA Proven Safety Countermeasures, please visit
https://safety.fhwa.dot.gov/provencountermeasures.

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Office of Safety logo: Safe Roads for a Safer Future
Page last modified on October 18, 2017
Safe Roads for a Safer Future - Investment in roadway safety saves lives
Federal Highway Administration | 1200 New Jersey Avenue, SE | Washington, DC 20590 | 202-366-4000