David Phillips and Kimberly Brewer (no pun intended) of the University of California, San Diego used data from the Fatality Analysis Reporting System (FARS) to compare blood alcohol contents (BAC, expressed as the percentage of alcohol in blood) in drivers involved in accidents. They concluded that even a BAC of 0.01 (one hundredth of one percent of the blood is alcohol) correlated with an increase in the severity of accidents.
The researchers used FARS data from 1994 to 2008, involving almost one and a half million people. FARS covers every fatal accident in the country, and records BAC down to 0.01. In the U.S., the legal BAC driving limit is 0.08 (many other countries have much lower limits). Phillips and Brewer found that the higher the BAC, the greater the chance that an accident would be a severe one. Even with a BAC of only 0.01, the ratio of severe injury to non-injury accident went up by a third, compared to accidents with sober drivers.
This is bad news for people who feel they can safely have one or two drinks with dinner before getting in a car. It turns out that the safest amount of alcohol for a driver is no alcohol.