It was only 10 years after mass production of automobiles began in the U.S. that the first drunk-driving law was passed in New York in 1910. Soon California followed as did many other states. These early laws didn’t define the level of intoxication. When blood alcohol content (BAC) levels were first introduced as a standard, laws in the 1930s and 1940s set the bar at .15% (it is now .08%). With the invention of the Breathalyzer in 1953 (replacing the 20-year old and relatively imprecise Drunkometer), modern testing of BAC was officially in place. The final evolution of DUIs occurred in the 1970s with the lobbying efforts of Mothers Against Drunk Drivers (MADD) who raised the age for drinking (and driving licenses), and lowered the BAC levels.
The law prohibiting drunk driving is most commonly known as DUI (for driving under the influence). However many states use other acronyms including:
Regardless of the acronym the meaning is generally the same -- driving under the influence of alcohol (or drugs). Don’t make the mistake of calling it “drunk driving.” If you’re arrested for a DUI, the D.A. does not need to prove you were drunk (whatever that means). All the D.A. has to show is that the driver drank enough booze or take enough drugs so that the driver’s ability to control the motor vehicle was impaired.
The Challenge. A DUI is a challenge for an accused driver because it usually includes two separate crimes, either one of which can be used to convict the driver: the "standard" DUI and the DUI Per Se. The “good” news is that a driver who is convicted of both of these offenses will usually only be sentenced for one.
In a standard DUI, the crime is accused of driving under the influence of alcohol to the extent it impairs physical and mental faculties. In most states, a DUI offense consists of the two elements:
Operating a vehicle: That is, driving or operating (sometimes even sitting or sleeping behind the wheel will suffice) a motor vehicle (typically a car, but a motor vehicle can also be a truck, a motorcycle, a golf cart, a bicycle, a tractor, a horse, and possibly even a skateboard),
As for the operation requirement, a police officer or a witness who saw you driving usually satisfies it. On occasion, however, especially after an accident, you may be out of the car when the officer arrives and the operation element is proven either because you admit you were driving or the officer deduces from all the evidence that you were driving.
In some states, you could be charged with a DUI even you’re found in the car with the engine turned off and the keys in your pocket. However, in other states where a DUI strictly requires you to be in control of a car while it is moving, you most likely would not be charged with a DUI.
In some but not all states, you must have been operating the vehicle on a public roadway. In other states it makes no difference where you were operating the vehicle even if it was on your own property. And the vehicle need not be a car. For instance, it is possible to be charged with DUI for operating a golf cart on a private golf course.
Under the influence: That is, while under the influence of an intoxicating beverage or drug, or with a blood alcohol level that exceeds the legal limit (0.08% in all states or 0.01% for those under 21 years of age in many states).
As for the “under the influence” requirement, the states differ on how this element is defined. For example, in California, the prosecution must prove that you were impaired to a degree that you couldn’t drive with the same caution or care as a sober person under the circumstances. In Colorado, the prosecutor needs to prove only that you were impaired to the “slightest degree.” And other states frequently use an “impaired to an appreciable degree” standard or some subtle variation of that. The fact is, you won’t really know the exact meaning of these words in your state’s laws unless you read the instructions that the judge will give the jury if you go to trial. Fortunately, these jury instructions likely are available in a local law library, or perhaps on your court’s website.
In a DUI Per Se, the driver is accused of driving while you have a blood alcohol content of .08 or greater even though the alcohol has had no effect on you. In other words, if the printout from a properly administered breath or blood test demonstrates that your BAC is over .08, you can be convicted of a DUI.
All states prohibit the operation of a vehicle on a public road if you have a blood alcohol content of more than .08. The offense occurs regardless of whether the alcohol had (or could have) any effect on your driving. Just driving with that particular blood condition can result in the same repercussions as described for driving under the influence. Not only is this a stand-alone offense, but having that amount of alcohol in your blood can be used to convince a jury that you were also under the influence.
As a general rule, most people charged with DUI plead guilty if a breath or blood test shows a BAC of .11 or higher, but are more inclined to fight if the amount is .10 or less. In fact in some states you get a boost if your blood alcohol content was less than a particular amount (typically .05) under laws that presume you to not to be under the influence.