Driving while impaired
Driving under the influence (DUI), driving while intoxicated (DWI), drunk(en) driving, drink driving, operating under the influence, drinking and driving, or impaired driving is the crime of driving a motor vehicle with blood levels of alcohol in excess of a legal limit ("Blood Alcohol Content", or "BAC"). Similar regulations cover driving or operating certain types of machinery while affected by drinking alcohol or taking other drugs, including, but not limited to prescription drugs. This is a criminal offense in most nations. Convictions do not necessarily involve actual driving of the vehicle.
In most jurisdictions, a quantitative measurement such as a blood alcohol content (BAC) in excess of a specific threshold level, such as 0.05% or 0.08%, defines the offense with no need to prove impairment or intoxication. In some jurisdictions, there is an aggravated category of the offense at a higher BAC level, such as 0.12%. In most countries, anyone who is convicted of injuring or killing someone while under the influence of alcohol or drugs can be heavily fined, as in France, in addition to being given a lengthy prison sentence. Many employers or occupations have their own rules and BAC limits; for example, the United States Federal Railroad Administration has a 0.04% limit for train crew. Certain large corporations have their own rules; for example, Union Pacific Railroad has their own BAC limit of 0.02% that, if violated during a random test or a for-cause test — for example, after a traffic accident — can result in termination of employment with no chance of future re-hire. Some jurisdictions have multiple levels of BAC for different categories of drivers; for example, the state of California has a general 0.08% BAC limit, a lower limit of 0.04% for commercial operators, and a limit of 0.01% for drivers who are under 21 or on probation for previous DUI offenses.
Many states in the U.S. and the Federal government of Canada have adopted truth in sentencing laws that enforce strict guidelines on sentencing, differing from previous practice where prison time was reduced or suspended after sentencing had been issued. Some jurisdictions have judicial guidelines requiring a mandatory minimum sentence. DUI convictions can result in multi-year jail terms and other penalties ranging from expensive fees to forfeiture of one's license plates and vehicle. Some jurisdictions require that drivers convicted of DUI offenses use special license plates that are easily distinguishable from regular plates. These plates are known in popular parlance as "party plates" or "whiskey plates".
The specific criminal offense may be called, depending on the jurisdiction, driving under the influence [of alcohol or other drugs] (DUI), driving under intense influence (DUII), driving while intoxicated (DWI), "operating vehicle under the influence of alcohol or drugs" (OVI), operating under the influence (OUI) operating while intoxicated (OWI), operating a motor vehicle while intoxicated (OMVI), driving under the combined influence of alcohol and/or other drugs, driving under the influence per se or drunk in charge [of a vehicle]. Many such laws apply also to motorcycling, boating, piloting aircraft, use of motile farm equipment such as tractors and combines, riding horses or driving a horse-drawn vehicle, or bicycling, possibly with different BAC level than driving. In some jurisdictions there are separate charges depending on the vehicle used, such as BWI (bicycling while intoxicated), which may carry a lighter sentence.
In the United States, local law enforcement agencies made 1,467,300 arrests nationwide for driving under the influence of alcohol in 1996, compared to 1.9 million such arrests during the peak year in 1983. In 1997 an estimated 513,200 DWI offenders were in prison or jail, down from 593,000 in 1990 and up from 270,100 in 1986.
Blood alcohol content (BAC)
With the advent of a scientific test for blood alcohol content (BAC), enforcement regimes moved to pinning culpability for the offense to strict liability based on driving while having more than a prescribed amount of blood alcohol, although this does not preclude the simultaneous existence of the older subjective tests. BAC is most conveniently measured as a simple percent of alcohol in the blood by weight. Research shows an exponential increase of the relative risk for a crash with a linear increase of BAC as shown in the illustration. BAC does not depend on any units of measurement. In Europe it is usually expressed as milligrams of alcohol per 100 milliliters of blood. However, 100 milliliters of blood weighs essentially the same as 100 milliliters of water, which weighs precisely 100 grams. Thus, for all practical purposes, this is the same as the simple dimensionless BAC measured as a percent. The per mille (promille) measurement, which is equal to ten times the percentage value, is used in Denmark, Finland, Norway and Sweden.
The validity of the testing equipment/methods and mathematical relationships for the measurement of breath and blood alcohol have been criticized.
Driving while consuming alcohol may be illegal within a jurisdiction. In some it is 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. There have been cases of drivers being convicted of a DUI when they were not observed driving after being proven in court they had been driving while under the influence.
In the case of an accident, insurance may be automatically declared invalid, i.e. the drunk driver is fully responsible for damages. Within the American system, citation for driving under the influence also causes a major spike in car insurance premiums – 94.1% in the first year, and still 63.5% higher by the third year.
The German model serves to reduce the number of accidents by identifying unfit drivers and removing them from until their fitness to drive has been established again. The Medical Psychological Assessment (MPA) works for a prognosis of the fitness for drive in future, has an interdisciplinary basic approach and offers the chance of individual rehabilitation to the offender.
George Smith, a London Taxi cab driver, ended up being the first person to be convicted of driving while intoxicated, on September 10, 1897. He was fined 25 shillings, which is equivalent to £71.33 in 2005 pounds.
Field sobriety testing
To attempt to determine whether a suspect is intoxicated, police officers may sometimes conduct what is known as a "field sobriety test".
A police officer in the United States must have probable cause to make an arrest for driving under the influence. In establishing probable cause for a DUI arrest officers frequently consider the suspect's performance of Standardized Field Sobriety Tests. The US National Highway Traffic Safety Administration (NHTSA) has established a standard battery of three roadside tests that are recommended to be administered in a standardized manner in making this arrest decision. The first test typically administered is the Horizontal Gaze Nystagmus test. When this test is conducted the officer is looking for the involuntary jerking of the suspect's eyes. The second test administered is the Walk and Turn (WAT) test. This test is a divided attention test and also measures balance. It requires the suspect to walk heel-to-toe on a line along with other instructions. The final test is the One Leg Stand (OLS). The OLS test requires the suspect to stand on one leg for 30 seconds and also measures balance, coordination, and similar to the WAT test, divides the suspect's attention.
Drunk driving law by country
- DR10, UK police code
- Driving license
- Drunk drivers
- Drunk walking
- DWI court
- Ignition interlock device
- Mothers Against Drunk Driving (MADD)
- National Motorists Association
- Remove Intoxicated Drivers
- Sobriety checkpoints
- Barron H. Lerner, One for the Road: Drunk Driving Since 1900. Baltimore, MD: Johns Hopkins University Press, 2011.
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