Driving Under the Influence, or DUI, is driving a car (or other motor vehicle) under the influence of alcohol and/or drug(s) to the extent that your motor skills, mental faculties and reaction times are so impaired that you cannot operate that motor vehicle safely. Terms such as Driving While Intoxicated (DWI), Operating Under the Influence (OUI), Operating While Intoxicated (OWI), drunk driving, and drinking and driving all relate to driving under the influence, but in certain cases they can have very distinct meanings depending on where you live.
DUI is a criminal offense in every state in the U.S. although laws for DUI vary depending on what state you live in. DUI arrests, subsequent DUI charges and DUI penalties can be significant and may include jail time, heavy fines, an ignition interlock device, and license revocation. In severe circumstances, driving under the influence can be a felony and, if someone is killed as a result of driving under the influence, can result in murder charges.
DRIVING UNDER THE INFLUENCE OF ALCOHOL
Driving under the influence of alcohol is the most common DUI offense. Alcohol is a central nervous system depressant and as a person consumes more and more alcohol a person’s intoxication level increases. Simply put, the more you drink, the drunker you get. As you become more intoxicated, your body undergoes changes that lead to being under the influence. Judgment, muscle coordination, memory, concentration, comprehension, vision and other senses all become impaired; reactions become delayed; and balance becomes difficult.
A person’s intoxication level is measured by blood alcohol content (BAC), which simply measures the percentage of alcohol in a volume of blood. For example, .15 BAC means a person has .15% of alcohol by volume in his or her blood. Alcohol does affect each person differently. Those with a “high” tolerance may seem more normal than a person with a “low” tolerance even though they have the same intoxication level.
The Significance of .08 BAC
In the U.S., all fifty states draw a line in the sand for driving under the influence of alcohol at .08 BAC. In certain states, one can still be prosecuted criminally if one is below a .08 BAC, but in those states the DUI penalties and DUI charges change significantly at .08 BAC.
Why is .08 significant? Based on scientific research, all persons, regardless of tolerance, at .08 BAC are under the influence of alcohol to the extent that a person cannot drive a car (or other motor vehicle) safely. So that is why at .08, you are considered per se under the influence for purposes of DUI.
Below .08 BAC
Scientifically speaking, at levels just under .08, such as .05-.07, most, but not all, persons are under the influence of alcohol to the extent that the person is unable to operate a motor vehicle safely. Some states may prosecute for lesser charges at this intoxication level. At levels lower than .05, it is difficult to prove that someone is “under the influence” of alcohol for purposes of DUI. Keep in mind that some states, however, have a zero tolerance law for drivers under age 21. Any amount of alcohol can put those drivers at risk, even as low as a .01.
DRIVING UNDER THE INFLUENCE OF DRUGS
Drugs can impair driving just as much as alcohol and driving under the influence of drugs, whether illegal, over the counter, or legally prescribed, can be prosecuted. Consumption of depressants such as marijuana, heroin, Vicodin, Oxycontin (oxycodone), codeine can affect the body in similar ways to alcohol and may result in charges relating to DUI drugs. Consumption of stimulants, such as methamphetamine or cocaine, can also affect the ability to operate a motor vehicle safely.
However, there is no scientific correlation between intoxication levels of drugs and the ability to operate a motor vehicle safely as there is with alcohol. For example, a person with a high level of marijuana does not necessarily indicate impairment by itself as alcohol does. This makes it more difficult to prove “being under the influence” of drugs to extent you can’t drive a motor vehicle safely.