The Safety Edge for Paving Projects


Unsafe Pavement Edges are a Serious Safety Problem. An estimated 11,000 Americans suffer injuries and 160 die each year in crashes related to unsafe pavement edges, at a cost of $1.2 billion. The true extent of the problem is difficult to assess because the role of the hazardous pavement edge in the sequence of events leading to a crash often is not documented.

What is the Definition of an Unsafe Pavement Edge?
An edge dropoff of four or more inches is considered unsafe if the roadway edge is at a 90º angle to the shoulder surface. Near vertical edge dropoffs of less than four inches are still considered a safety hazard to the driving public and may cause difficulty upon reentry to the paved surface.

How do Unsafe Edges Cause Crashes?
Drivers who slip off a resurfaced road onto an unimproved shoulder are likely to lose control as they attempt to climb onto the roadway. The pavement edge creates a “scrubbing” condition that must be overcome through over-steering. As drivers over-steer to reenter the roadway, they are prone to lose control of the vehicle. Compounding the danger, the rear wheel may catch the edge of the shoulder, swinging the car around. These actions may cause the car to veer into the adjacent lane, where it may collide or sideswipe oncoming cars, overturn, or run off the road and crash. Adopting a standard contract specification requiring a 30-35º angle asphalt fillet along each side of the roadway in all resurfacing projects is a simple and cost-effective way to assure pavement edge safety.

Solutions to the pavement edge drop-off hazard are to:
  • Require a 30-35º angle asphalt fillet “Safety Edge” as a contract specification in all pavement resurfacing projects; and
  • Routinely resurface shoulders when roadways are resurfaced.

The asphalt fillet provides a safer roadway edge, and a stronger interface between the roadway and the shoulder. The cost of an asphalt fillet is minimal in comparison to the total amount of the resurfacing contract, and pays back in countless dollars saved from reduction of fatalities, injuries, property damage and lawsuits. An inexpensive way to assure pavement edge safety is to specify a 30º- 35º angle asphalt fillet "Safety Edge." The fillet ties the existing shoulder into the resurfaced roadway and allows a vehicle to reenter the roadway safely. Highway agencies are able to restore the shoulder after the resurfacing project is completed.