Citation

Moler S. Accid. Reconstr. J. 2008; 18(2): 33-36.

Copyright

(Copyright © 2008, Accident Reconstruction Journal)

DOI

unavailable

PMID

unavailable

Abstract

When a vehicle slips off the pavement and onto an unpaved shoulder, the steep edge can make it difficult for a driver to reenter the paved travel lane safely. Studies show that when a driver encounters a steep pavement edge, he or she attempts to return immediately to the paved travel lane but in doing so tends to oversteer, causing intense rubbing or scrubbing of the vehicle tires against the pavement edge. This initially prevents the vehicle from climbing back onto the pavement and the oversteering can cause loss of control at the moment when the right rear tire climbs back onto the pavement, causing the vehicle to fishtail or go into a broadside skid. Although relatively rare compared with other crash types, pavement-edge dropoff-related crashes tend to be more severe. In fact, these crashes are more likely than others on similar roadways to result in serious injuries and are 2-3 times more likely to be fatal, primarily because the vehicle often leaves the roadway, rolls over, hits a roadside object, or is involved in a head-on collision. This article describes the installation of the safety edge, a relatively easy, inexpensive countermeasure to steep pavement edges to reduce crashes on rural 2-lane roads. The safety edge is a 30- to 35-deg tapered asphalt wedge or fillet, applied along each side of the roadway during resurfacing projects. The safety edge not only provides an angled and compacted transition that eliminates the abrupt dropoff, but also provides for a stronger and more stable pavement edge. This makes it easier for drivers to maneuver their vehicles safely back onto the highway. By offering a tapered, rather than vertical, transition between the paved surface and the unpaved shoulder, the safety edge is a low cost means of improving safety on paved 2-lane highways.