Driving Under the Influence (DUI) Law and Legal Definition

DUI or Driving under the influence refers to the act of operating a vehicle after consuming alcohol or other drugs. This drunken driving charge is a criminal offense in most countries.

A person is guilty of DUI if s/he drives or is in actual physical control of a motor vehicle and is under the influence of alcoholic beverages or any chemical or controlled substance to the extent that his/her mental faculties are impaired or when his/her blood alcohol level (BAC) is above the legal limit for the state.

The penalties for being convicted of DUI depend on prior criminal and traffic records, the level of alcohol in blood, and the specific facts of the case at hand. Following a successful conviction for DUI charges, many first time offenders will be required to attend AA meetings or special classes. In some cases, a breathalyzer may be attached to their car's ignition to prevent the car from starting when they have consumed alcohol. Higher BAC levels can double the penalties under some DUI laws.

Depending on the jurisdiction, this criminal offense may also be referred to as driving while intoxicated ( DWI ), driving while impaired (also DWI ), operating a motor vehicle while intoxicated ( OWI ) or operating a motor vehicle while intoxicated ( OMVI ).

The following is an example of a State Statute (California) on DUI:

Cal Veh Code § 23152

(a) It is unlawful for any person who is under the influence of any alcoholic beverage or drug, or under the combined influence of any alcoholic beverage and drug, to drive a vehicle.

(b) It is unlawful for any person who has 0.08 percent or more, by weight, of alcohol in his or her blood to drive a vehicle.

For purposes of this article and Section 34501.16, percent, by weight, of alcohol in a person's blood is based upon grams of alcohol per 100 milliliters of blood or grams of alcohol per 210 liters of breath.

In any prosecution under this subdivision, it is a rebuttable presumption that the person had 0.08 percent or more, by weight, of alcohol in his or her blood at the time of driving the vehicle if the person had 0.08 percent or more, by weight, of alcohol in his or her blood at the time of the performance of a chemical test within three hours after the driving.

(c) It is unlawful for any person who is addicted to the use of any drug to drive a vehicle. This subdivision shall not apply to a person who is participating in a narcotic treatment program approved pursuant to Article 3 (commencing with Section 11875) of Chapter 1 of Part 3 of Division 10.5 of the Health and Safety Code.

(d) This section shall become operative only upon the receipt by the Secretary of State of the notice specified in subdivision (f) of Section 23152, as added by Section 25 of Chapter 1114 of the Statutes of 1989.