Commentary - Deadly Drop-offs



> Pavement edge drop-offs can be deadly for motorists
> Safety tips when you're over the edge

Pavement edge drop-offs can be deadly for motorists

Driver, 24, ran off the right side of the roadway and overcorrected, causing the vehicle to overturn." "Driver, 59, died when the vehicle she was driving ran off the right side of the road and she overcorrected. Vehicle returned to the roadway and overturned." "Driver, 30, died when the vehicle he was driving traveled off the roadway. He overcorrected, causing the vehicle to travel off the other side of the road and strike a rock bluff."

While crashes related to pavement edge drop-off are relatively infrequent, they are often severe. Drivers who veer off the road and into the shoulder can be caught by surprise when one or two of their wheels drop off the pavement. Even if the drop-off is only a couple of inches, the resulting overcorrection can be fatal. A study sponsored by the AAA Foundation for Traffic Safety found that pavement edge drop-off related crashes are substantially more likely than other crashes on similar roadways to result in serious injuries, and are more than twice as likely to be fatal. Such drop-offs are hazardous because the significant vertical differences between surfaces can affect vehicle stability and reduce a driver's ability to handle his or her car.

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 where the shoulder has not yet been leveled with the paved road surface. Although they can occur on any roadway, drop-offs are more common on rural two-lane roads with narrow lanes and shoulders.

A driver can veer off the road for any number of reasons. Pavement edge drop-offs, especially if they are two inches or deeper, can increase the risk of a crash and make it difficult for a driver to return to the road safely, the study found.

A typical crash occurs when the driver attempts an immediate return to the roadway and the tire sidewall is forced into the pavement drop-off edge-a situation called "tire scrubbing." When this happens, some drivers overreact and increase their steering angle, thinking a sharper turn back onto the road is the solution. In fact, this can cause the driver to lose control and cross the road into oncoming traffic. It can also result in a rollover.

Safety tips when you're over the edge

When encountering a pavement edge drop-off, it's not about returning to the road quickly; it's about returning to the road safely. Don't panic or swerve back onto the road, especially at high speed. This can easily cause you to lose control.

Instead, motorists are advised to continue steering a straight line and slow down gradually, not abruptly. Braking hard while the tires are on different surfaces can cause the vehicle to skid. If traffic is heavy, drive all the way on to the shoulder and wait until there is a gap. Then you can drive back onto the road safely.

The AAA Foundation for Traffic Safety's complete report on crashes related to pavement edge drop-offs can be downloaded at www.aaafoundation.org (enter "pavement edge" in the search box). Numerous studies and resources on a wide range of traffic safety issues are available at the same website.