page_title: Drunk driving law by country
section_title: United States
hierarchical_section_title: Drunk driving law by country / Americas / North America / United States
caption_attribution_description: English: Drunk driving safety poster. "Don't mix 'em".
context_page_description: The laws of driving under the influence vary between countries. One difference is the acceptable limit of blood alcohol content before a person is charged with a crime.
context_section_description: United States: Depends on state, 0.08% or 0.05% BAC by volume
  In the United States, the blood alcohol level at which all states make it unlawful to operate a motor vehicle is 0.08, although it is possible to be convicted of impaired driving at a lower blood alcohol level. Some states define two impaired driving offenses.
  The first is the traditional offense, variously called driving under the influence of alcohol (DUI), driving while intoxicated/impaired (DWI), operating under the influence (OUI), or operating while intoxicated/impaired (OWI).
  The second and more recent is the so-called illegal per se offense of driving with a blood alcohol concentration (BAC) by volume (mass of alcohol/volume of blood) of 0.08% (previously 0.10%) or higher.
  The first offense requires proof of intoxication, although evidence of BAC is admissible as rebuttably presumptive evidence of that intoxication; the second requires only proof of BAC at the time of being in physical control of a motor vehicle. An accused may potentially be convicted of both offenses as a result of a single incident, but may only be punished for one. The differences between state penalties still varies. Wisconsin, for instance, is the only state that continues to treat first offense drunk driving arrests as forfeiture.
  Some states also include a lesser charge of driving with a BAC of 0.05%; other states limit this offense to drivers under the age of 21. All states and DC also now have zero tolerance laws: the license of anyone under 21 driving with any detectable alcohol in their bloodstream (BAC limits of 0.01% or 0.02% apply in some states, such as Florida.) will be suspended. In 2009, Puerto Rico joined these states, setting a limit of 0.02 for drivers under 21, despite maintaining a legal drinking age of 18.
  The blood alcohol limit for commercial drivers is 0.04%. Pilots of aircraft may not fly within eight hours of consuming alcohol, while under the impairing influence of alcohol or any other drug, or while showing a blood alcohol concentration equal to or greater than 0.04 grams per decilitre of blood.
  Utah became the first U.S. state to lower the legal limit to .05% BAC by volume on 24 March 2017. The law went into effect on 30 December 2018. The bill's passage, HB155, was controversial in the state. A poll published on 29 July 2017 found 50 percent of Utahns supported the new law, but 47 percent opposed it.
  In most states, the timing of the chemical test for suspected drunk driving is important because the law mandates a result within a given time period after the driving stopped, usually two hours.
caption: A 1937 poster warns U.S. drivers about the dangers of mixing alcohol and driving
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