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 limited roadside surveys.
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 Administr
