DUI/DWI is regulated on a state-by-state basis, with different states setting different limits for different offenses. Some jurisdictions set substantially lower blood alcohol content (BAC) percentages for minors to be convicted of drunk driving. In every jurisdiction, there are circumstances where parties charged or convicted of drinking and driving can lose their license. In addition, DUI/DWI convictions typically lead to significant increases in insurance premiums.
The Traffic Stop
Generally, police must have probable cause to make a traffic stop. This means they must have a reasonable belief that criminal activity is taking place, or that the person has engaged in criminal acts. However, the U.S. Supreme Court has upheld sobriety checkpoints, even though police have no probable cause. A number of states, though, have rejected sobriety checkpoints as violating state constitutions.
Once you have been stopped, police officers may ask if you have been drinking. Regardless of your answer, they may ask you to take a field sobriety test, or submit to a breathalyzer or BAC test. You always have the right to refuse, but you may risk the immediate loss of your license, if you do.
If you are arrested, police must give you certain warnings, as set forth by the U.S. Supreme Court in the Miranda opinion. You must be notified that you have the right to remain silent, that anything you say may be used against you, that you have the right to have an attorney present, and that one will be appointed for you, if you cannot afford one.
A DUI involves a two-part process: the administrative hearing regarding your driving privileges, and the criminal proceeding to determine guilt or innocence, and set penalties. Typically, you must file a notice with the state agency that regulates driving records, and must do so within a minimum period of time (usually 10-15 days). If you fail to do so, your license will typically be revoked.
At the criminal proceeding, you can enter any evidence to exonerate you or to mitigate the circumstances of a conviction. The penalties in a criminal proceeding usually depend on the severity of the crime, and on whether you are a repeat offender.