This refers to an abbreviation for driving under the influence. (DUI) The most common impairing substance is usually ALCOHOL. However, many states also prohibit DUI DRUGS and DUI TOXIC VAPORS (sniffing or huffing paint fumes, butane, paint thinner and similar chemicals).
Driving under the influence (of drugs or alcohol)
alcohol consumption ( in alcohol consumption: United States )
...alcohol, most of them intended to interfere with the availability of beverages at certain times, in certain places, or to certain classes of persons. An example is the tolerance sometimes found for driving under the influence of alcohol. In response to the large percentage of automobile fatalities involving alcohol consumption—according to some studies alcohol use was present in more than...
n. commonly called "drunk driving," it refers to operating a motor vehicle while one's blood alcohol content is above the legal limit set by statute, which supposedly is the level at which a person cannot drive safely. State statutes vary as to what that level is, but it ranges from .08 to .10 for adults, which means a 8/100ths to one-tenth of one percent by weight of alcohol to the weight of blood. This is translated into grams of alcohol per 100 milliliters of blood in tests of blood or urine sample, or grams of alcohol per 210 liters of air in a "breathalizer" test. A combination of the use of alchol and narcotics can also be "under the influence" based on erratic driving. Driving on private property such as a parking lot is no defense, but sitting in a non-moving vehicle without the ignition on probably is (sometimes resulting in a charge of "drunk in and about a vehicle"). This is a misdemeanor and is variously referred to as DUI, driving while intoxicated (DWI), drunk driving, or a "deuce".
Driving under the influence is a serious health hazard. In the United States, for example, alcohol is estimated to play a role in 39 percent of vehicle-related deaths and to cost $51 billion annually. More recently it has been reported that alcohol contributes to nearly 30 percent of all Canadian traffic fatalities and 44 percent of traffic fatalities in the United States. 
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 states in the U.S. have adopted truth in sentencing laws that enforce strict guidelines on sentencing. For example, if a defendant is sentenced to ten years, he or she will be in prison for that entire time. This is different from past practice where prison time was reduced or suspended after sentencing had been issued.