The specific criminal offense may be called driving while intoxicated (DWI), driving while impaired (also DWI), operating while intoxicated (OWI), operating a motor vehicle while intoxicated (OMVI), driving under the influence [of alcohol or other drugs] (DUI), driving under the combined influence of alcohol and/or other drugs, driving under the influence per se or drunk in charge [of a vehicle] depending on the jurisdiction. These laws can also apply to boating, piloting aircraft, and even bicycling in some states such as California.
TESTS ESTABLISHING DUI
In the past, guilt was established by observed driving symptoms, such as weaving. If an officer suspects impairment a field sobriety test, such as walking a straight line heel-to-toe or standing on one leg for 30 seconds may be given at which time the officer can give a subjective opinion of one’s impairment. Starting with the introduction in Norway in 1936 the world’s first per se law which made it an offense to drive with more than a specified amount of alcohol in the body, objective chemical tests have gradually supplemented the earlier purely judgmental ones. Limits for chemical tests are specific for blood alcohol concentration or concentration of alcohol in breath.
Today’s statues commonly provide for two separate and distinct criminal offenses. The first is the traditional “drunk driving” offense, consisting of driving under the influence of alcohol and/or drugs. Evidence to support this crime generally comes from the officer’s observations (such as erratic driving, slurred speech, unsteady gait,), performance on field sobriety tests, and a legal (and generally rebuttable) presumption of intoxication from a blood alcohol test result over the legal limit. The second offense is the more recent so-called “per se” offense: rather than focusing on impairment the crime consists entirely of having a given blood alcohol content (BAC) at the time of driving, regardless of the individual’s tolerance to alcohol. Since 2002 it has been illegal in all 50 US states to drive with a BAC that is 0.08% or higher. Both offenses may be charged, and the defendant may be convicted of both; if a blood alcohol test result was not obtained, only the traditional “DUI” offense will be charged.
Driving while consuming alcohol is generally illegal, though driving after drinking remains legal. In California, it is also illegal for an open container of an alcoholic beverage to be in the passenger compartment of a motor vehicle or in some specific area of that compartment.