(This article is reproduced, with permission, from the website of the Insurance Institute for Highway Safety at http://www.highwaysafety.org.)

About a third of motor vehicle deaths involve vehicles leaving the roadway and hitting fixed objects such as trees or utility poles alongside the road. Almost all such crashes involve only 1 vehicle. Roadside hazard crashes occur in both urban and rural areas but are mostly a problem on rural roads. They're most likely to occur on curves and/or downhill road sections. More than a third involve a vehicle that rolls over, and about a third involve occupant ejection. Trees are by far the most common objects struck in roadside hazard crashes.

Alcohol is a frequent contributing factor in these crashes. Motorists also run off the road because of excessive speed, fatigue, or inattention. Efforts to reduce these driver errors are only somewhat effective, so it's important to shield or remove stationary objects or avoid putting them along roads in the first place, especially roads where vehicles are more likely to leave the pavement.

The following facts are based on analysis of data from the U.S. Department of Transportation's Fatality Analysis Reporting System:

• 11,809 people died in roadside hazard crashes in 1998, essentially unchanged from 1997 and about 8 percent more than in 1975.
• The proportion of motor vehicle deaths involving roadside hazards has remained between 28 and 30 percent since 1979.
• Forty-five percent of drivers killed in roadside hazard crashes in 1998 had blood alcohol concentrations at or above 0.10 percent.
• Drivers of 43 percent of the vehicles in fatal roadside hazard crashes in 1998 were men younger than 35.

CRASH TYPES

• Ninety-seven percent of roadside hazard crash deaths in 1998 occurred in single-vehicle crashes.
• Forty percent of deaths in roadside hazard crashes in 1998 involved vehicles rolling over.
• Thirty-two percent of deaths in roadside hazard crashes in 1998 involved occupant ejections.
• Two-thirds of deaths in roadside hazard crashes in 1998 occurred in frontal impacts.

OBJECTS STRUCK

• Trees are the most common hazard. Twenty-eight percent of deaths in roadside hazard crashes in 1998 involved a vehicle striking a tree.
• Embankments and guard rails are the next most common hazards. Each accounted for about 10 percent of deaths in roadside hazard crashes in 1998.

ROAD TYPES

• Forty-eight percent of deaths in roadside hazard crashes in 1998 occurred on major roads, 34 percent occurred on minor roads, and 18 percent occurred on freeways including interstates.
• Sixty-six percent of deaths in roadside hazard crashes in 1998 occurred on rural roads.
• Forty-three percent of deaths in roadside hazard crashes in 1998 occurred on curves.
• Seventeen percent of deaths in roadside hazard crashes in 1998 occurred on wet or slippery roads.
• Fifty-five percent of deaths in roadside hazard crashes in 1998 occurred on roads with speed limits 55 mph or faster.

TABLES