While the legal blood-alcohol content (BAC) for drivers in the United States is 0.08 percent, David Phillips, Ph.D., a University of California, San Diego sociologist, points out that drivers with blood-alcohol levels much lower than 0.08 percent are more likely to be involved in crashes of greater severity than those involving entirely sober drivers.
Phillips, along with coauthor Kimberly M. Brewer of UC San Diego, studied Fatality Analysis Reporting System (FARS) data on fatal car accidents in the United States. The data covered nearly 1.5 million people between 1994-2008, including reports on people with blood-alcohol content in increments of 0.01.
“Compared with sober drivers, buzzed drivers are more likely to speed, more likely to be improperly seat-belted and more likely to drive the striking vehicle, all of which are associated with greater severity,” Phillips explained.
Barely Detectable, Very Dangerous
Phillips’ research indicates that accidents are 36.6 percent more severe even when alcohol was “barely detectable” in a driver’s blood. A BAC of just 0.01 accounted for 4.33 serious injuries for every non-serious injury versus 3.17 for sober drivers.
Phillips and Brewer also noted a strong “dose-response” relationship between all these factors. For example, the greater the driver’s BAC, the greater the average speed of the driver and the greater the severity of the accident.
In general, accident severity is significantly higher on weekends, between 8 p.m. and 4 a.m. and in the summer months, June through August. But when the researchers standardized for day of the week, time of day and month, the relationship between BAC and more dangerous car accidents remained. The findings persisted even when variables as inattention and fatigue were excluded from the analysis.
Lower the Limit?
“Up till now, BAC limits have been determined not only by rational considerations and by empirical findings but also by political and cultural factors,” Phillips said, citing as evidence that the U.S. national standard of 0.08 is relatively recent and that BAC limits vary greatly by country. In Germany, the limit is 0.05; in Japan, 0.03; and in Sweden, 0.02.
“We hope that our study might influence not only U.S. legislators, but also foreign legislators, in providing empirical evidence for lowering the legal BAC even more,” Phillips said. “Doing so is very likely to reduce incapacitating injuries and to save lives.”
The study was published in the journal Addiction.