After someone consumes alcohol, it is absorbed into the bloodstream. Blood Alcohol Content, or BAC, refers to the amount of alcohol in a person’s blood. BAC is typically denoted as a percentage, with .10 meaning a tenth of a percent of a person’s blood is alcohol. Once in the bloodstream, alcohol affects behavior and impairs judgment and reflexes. For that reason, individual states have set legal BAC limits, as well as punishments for driving a vehicle while over that limit. In 1983 Utah, along with Oregon, were the first states to lower the limit from .10 to .08. By 2005 every other state had lowered the limit to .08 as well. In 2017 the Utah Legislature passed a bill to make Utah the first state in the United States to lower the limit to .05. The new limit takes effect in 2018.
Utah may have been the first state in the United States with a .05 BAC limit, but most of the developed world has been at the .05 limit, or even lower, for many years. In fact, every European country except one has a limit of no more than .05, and nine of them have limits lower than that, with four countries all the way down to 0. In Canada, every province but Quebec has a limit of no more than .05 as well.
While impairment begins with the first drink, and alcohol absorption can vary based on gender, weight, the type of beverage consumed, and other factors, in general a person would be able to have a drink with dinner and still be under the legal .05 BAC limit. In fact, an average man could have as many as four drinks over a two-hour period and still be under the legal limit.
As the limits in the U.S. have lowered, so too have the incidence of fatal vehicle accidents, falling from a high of 21,000 in 1982 to just under 10,000 in 2014, which is about a third of all vehicle fatalities . Unfortunately, alcohol-related deaths have been on the rise since 2011. But the numbers of fatal accidents or even DUI arrests don’t tell the whole story. The Centers for Disease Control and Prevention surveys people on whether they’ve driven after having too much to drink, and calculated there were 111 million such instances in 2014. So there is still work to be done to change the public’s view of the dangers of alcohol-impaired driving. Indeed, the risk of getting in a fatal accident is up to 20 times greater for someone who is over the .05 limit. Largely because of this increased risk, the National Transportation Safety Board recommended in 2013 that all states lower the legal BAC limit to .05.
NTSB Safety Report on Eliminating Impaired Driving – FAQ
MADD: What is BAC?
Texas Alcoholic Beverage Commission: Approximate Blood Alcohol Content Charts
NCBI Research Report: The Effectiveness of .05 BAC Limit