Safety edge treatment

Safety issue

Safety edge treatment.      
Safety edge treatment
Asphalt road with and without safety edge

Roadway departure crashes account for approximately 50% of fatal crashes each year on the nation's highways. One type of roadway departure crash can be due to an edge drop between the paved surface and the gravel shoulder. A vertical edge drop as little as 2.5 inches can cause a driver to over steer in an attempt to reenter the pavement. Once the vehicle does enter the roadway it is an abrupt jump onto the roadway that can cause a vehicle to shoot into opposing traffic.

Safety design

Safety Edgesm is a sloped wedge of pavement added to the outside edge of a lane or outside edge of a paved shoulder. When done correctly, simply shaping the edge of the pavement to 30 degrees can eliminate the problem of vertical drop-off. T​he Safety Edgesm provides a smooth transition for all vehicles to return to the roadway. Studies testing the performance of Safety Edgesm indicate a 13% reduction in all crashes on rural two-lane highways.​


  • Reduction in overall crashes on two lane rural roadways.
  • Pavement is less likely to have edge failures.
  • Low cost of installation.
  • Less edge damage during construction.
  • Smoother transition back onto roadway.

Where are they being used?

  • Installed on asphalt highways with narrow or unpaved shoulders.


Erik Emerson, P.E.
WisDOT State Standards Development Engineer
(608) 266-2842