In 2000, there were 6.4 million automotive vehicle crashes known to the police, the National Highway Transportation Safety Administration reports. That averages out to 17,500 per day--or one every five seconds. Of these, only two-thirds of 1 percent involved fatalities. About one third resulted in injuries, while the rest involved only property damage.
From 1990 to 2000, vehicle-miles traveled rose by nearly 29 percent, the number of vehicles registered by 17 percent and population by almost 13 percent. For both crashes involving injuries and those involving only property damage, however, the annual numbers remained remarkably stable. The total number of vehicles involved in all types of accidents rose only 0.5 percent and the number of fatal accidents fell 3.2 percent. The number of persons killed in traffic accidents declined even more, by 6.3 percent.
As to the accident rate per 100 million miles driven, among passenger cars, the rate decline was 25.8 percent; for large trucks, it was 15.6 percent; and for small trucks (which include sport utility vehicles), it was 4.9 percent. That adds up to an overall decline of 21.5 percent.
Why have traffic accidents in the United States not risen along with total vehicle-miles driven? Several different forces are responsible.
- Improvements in road design. The construction of interstate highways beginning in 1956 revolutionized the safety of U.S. long- distance driving. Many two-lane roads were replaced by interstates that always have at least two lanes in each direction and a physical separation between lanes going the opposite direction. Interstates also have no intersections where traffic on one road crosses directly into the path of traffic on another. In addition, curves on interstate highways were graduated enough to allow high-speed movement with little risk of flying off the road.
- Less use of alcohol by Americans generally, and by automobile drivers in particular. From 1980 to 1997, per capita consumption of alcohol in the United States fell 20 percent. Starting in the early 1980s, many states passed tougher penalties for driving under the influence and carried out educational and instructional campaigns publicizing those new laws. Consequently, the share of all traffic fatalities related to alcohol consumption dropped from 58 percent in 1982 to about 30 percent in 2001.
- Greater use of safety restraints in vehicles. In 1990, about 64 percent of drivers in injury and damage-only crashes were wearing seatbelts. By 2000, 82 percent were using them. Other laws requiring safety seats for children were also passed, and safety seat loaner programs were established in many states. The addition of air bags and improved crash resistance in car designs have made a difference as well.
- Increases in the number of law enforcement personnel assigned to manage traffic. In 10 states covered by a special NHTSA investigation of traffic safety practices, the number of sworn police officers rose 19 percent from 1980 to 1993. Officers in these 10 states made 33 percent more DUI arrests and issued 14 percent more speeding citations during this period.
- Slower traffic due to increased congestion. Congestion can have two opposite effects on accidents. On the one hand, as traffic slows down, the chances of major accidents are reduced. On the other hand, so- called "secondary" accidents often occur when traffic has been slowed or stopped by a "primary" accident.
- Greater use of traffic-management centers. Many states have created traffic "war rooms" that collect visual data from remote TV cameras, speed data from buried sensors and phone reports from motorists to identify accidents. These centers then help direct special vehicles to incident scenes to quickly remove obstacles from traffic lanes and coordinate remedial efforts among related agencies.
