Laws & Penalties DUI, DWI and Zero Tolerance Laws by State

The terms "driving under the influence" (DUI) and "driving while impaired" (DWI) describe the criminal act of operating an automobile while one's ability is impaired by the effects of alcohol, illegal drugs, prescription medicine or other substance. DUI and DWI are illegal in all 50 states, with each state enacting its own set of DUI/DWI drinking and driving laws.

Q: What is the difference between a DUI and DWI?

A: Some states make a distinction between DUI and DWI and, in those that do, DWI usually refers to offenses specifically for alcohol consumption ("intoxication" in DWI) and DUI refers to impairment from drugs, alcohol or other substances (the "influence" in DUI.) In many states, a driver may be charged with being unlawfully impairment even though the influence does not rise to the level of actual intoxication. Thus a DUI could be seen as a lesser offense for driving under the influence of alcohol and DWI for a more serious offense of driving while being legally intoxicated. DUI would be an appropriate charge when a driver is under the influence of prescription medication which impairs the driver's ability to maintain reasonable control and operation of the vehicle.

Q: At what point is a driver considered to be legally drunk or intoxicated?

A: For alcohol related offenses, a charge is determined based upon the blood alcohol content (BAC) or blood alcohol level (BAL) of the driver at the time the driver is stopped by a police officer. Every state has "per se" intoxication laws that deem the driver as being automatically guilty of DUI or DWI. All states have lowered the BAC/BAL level to .08 or above which, on its face, is evidence of per se of legal intoxication. The police officer can arrest the motorist for DUI or DWI on that reading alone with no other proof required such as a field sobriety test. This is in contrast to the circumstantial evidence for which a police officer can arrest a driver on DUI charges by using failed results of "field sobriety tests" and may include the police officer witnessing the driver swerving, driving erratically, having slurred speech or the inability focus while be questioned. While it is more difficult to make a case without the BAC or BAL level, a driver can be convicted of a DUI or DWI charge after failing a field sobriety test.

Q: What are "Zero Tolerance" laws?

A: Every state has Zero Tolerance laws, making it unlawful for any driver under the legal drinking age to drive with a BAC above 0.00 – most being 0.01 or 0.02. For example, a teenager may claim to be completely unimpaired while operating a motor vehicle, even though the teenager's BAC was only 0.02. However, it is unlawful for the teenager to possess or drink alcohol at any level, especially when driving.

Blood Alcohol Content / Level State Laws Chart