Research by the AAA Foundation for Traffic Safety has found that roads with pavement edge drop-offs can make vehicle crashes more serious than other types of roads. In addition, crashes on roads with drop-off edges were more than twice as likely to be fatal.
Characterized by a shoulder that is lower than the edge of the paved road surface, pavement edge drop-off can be caused by pavement breaking, erosion and wear of unpaved shoulders, inadequate maintenance, or resurfacing projects that neglect to keep shoulders level with the paved road surface, the group’s research found. Although they can occur on any roadway, they are more common on rural two-lane roads with narrow lanes and shoulders, said Peter Kissinger, AAA Foundation president & CEO
According to the study, a pavement edge drop-off, especially two inches or deeper, can increase the risk of a vehicle crash and make it difficult for a driver to return to the road safely. Though crashes related to pavement edge drop-off are relatively infrequent, they are often very severe, said Kissinger.
The group’s report recommends agencies adopt a policy of providing paved shoulders, with a minimum width of two feet—or wider if conditions warrant—wherever practical, and endorsed the incorporation of a beveled edge, such as the Federal Highway Administration’s (FHWA) “safety edge,” in all roadway resurfacing projects to prevent the occurrence of severe drop-offs at pavement edges.
According to FHWA that state and local jurisdictions should consider using a safety edge on resurfacing projects to help eliminate edge drop-offs as the majority of highway fatalities occur on two-lane rural roads – the ones most susceptible to drop-offs forming.
“The safety edge is a low-cost construction technique that has the potential to save lives,” said John Baxter, director of the FHWA Office of Safety Design.