Alcohol Consumption and Traffic Crashes

by David J. Hanson, Ph.D.

The Insurance Institute for Highway Safety in an unbiased evaluator of all the causes of traffic crashes, injuries and deaths. The insurance companies that sponsor its work are interested in reducing traffic accidents. Neither the insurance industry nor the Institute has an ideological agenda to promote.

The following information is from the Institute’s web site Question and Answer page about alcohol:

What proportion of all motor vehicle crashes is caused by alcohol? It is impossible to say with certainty. Although alcohol is known to increase crash likelihood, its presence is neither necessary nor sufficient to cause a crash. Every crash in which a driver has a high BAC is not caused by alcohol. To learn the number of crashes caused by driving at various BACs, it would be necessary to find out how many trips that do not involve crashes are driven by people with positive BACs -- something that is only measured periodically in roadside surveys or special studies of motorists not involved in crashes.

What proportion of motor vehicle crashes involves alcohol? The most reliable information about alcohol involvement comes from fatal crashes. In 2002, 32 percent of fatally injured drivers had BACs of at least 0.08 percent. Although alcohol may not have been a causal factor in all of the crashes, this statistic is frequently used to measure the change over time in alcohol involvement in fatal crashes.

In 2002, the National Highway Traffic Safety Administration (NHTSA) estimated that 35 percent of all traffic deaths occurred in crashes in which at least one driver or nonoccupant had a BAC of 0.08 percent or more and that any alcohol was present in 41 percent of all fatal crashes in 2002.Such statistics are sometimes cited as proof that a third to half of all fatal crashes are caused by "drunk driving" and that none of the crashes that involve alcohol would occur if the alcohol were not present. But this is incorrect and misleading because alcohol is only one of several factors that contribute to crashes involving drinking drivers. Furthermore, some fatally injured people in alcohol-related crashes are pedestrians with positive BACs, and these fatalities still would occur even if every driver were sober.

Alcohol involvement is much lower in crashes involving nonfatal injuries, and it is lower still in crashes that do not involve injuries at all. 1

Ten percent (10%) of all people who receive injuries in traffic accidents do so in alcohol-related crashes, according to NHTSA estimates. It is estimated that 3.22% of these injury-producing crashes involve intoxicated drivers.

Seven percent (7%) of all traffic accidents involve alcohol use, according to NHTSA estimates. It is estimated that 2.25% of all vehicular crashes involve intoxicated drivers.

These statistics are all estimates based on incomplete information. Often they are estimates based on other estimates. However, 12.8% of all drivers involved in fatal accidents in the U.S. during 2001 are known to have been intoxicated according to the BAC laws (.10 or .08) of their state. This number is based on a systematic examination of the official records of each and every accident involving a fatality during that year in the US. It is based on factual evidence rather than on estimates or guesses.

The higher numbers commonly reported in the press refers to accidents in which NHTSA believes that some alcohol has been consumed by someone associated with the accident. For example, if a person who was believed to have consumed any alcohol is stopped at a red light and is rear-ended by an inattentive completely sober driver, that accident is considered to be alcohol-related.

Alcohol consumption, cell phone use, drowsy driving, aggressive driving, and drugged driving are all important but preventable causes of traffic accidents, injuries and deaths. There has been a dramatic and continuing drop in alcohol-related traffic crashes, but much more needs to be done to prevent drunk driving,

However, virtually ignored have been the other major causes of vehicular crashes. For example, using a cell phone is even more dangerous than driving while intoxicated. We can and must do even more to reduce traffic crashes from all causes.

A person who dies in a traffic crash is just as dead whether the accident was caused by a drunk driver, a cell phone user, an aggressive driver, or a drugged driver. They must all be stopped.

 

References and Readings

filed under: Drinking and Driving

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