DUI or Driving while under the influence, the influence of what? Alcohol primarily but it can also mean under the influence of marijuana, cocaine, heroin, some prescription medications, and a variety of other drugs. Alcohol is a powerful depressant, it slows the brain down and actually suppresses the brains ability to control the body's' coordination and reactions. The brains ability to process what it's observing is compromised, making it difficult to react to changing road conditions, anticipate what other cars on the road are going to do or even drive in a straight line.

If the officer believes that the driver has been drinking they will ask the driver to submit to what's called a BAC test (Blood Alcohol level) if the test comes back .08% or higher then the driver is legally over the limit in most states. If the driver refuses to take the test he or she may automatically lose their license, and it would count against them when the case is brought to court. In some states the refusal to take the BAC test (even if later you are proven innocent of driving under the influence) will result in criminal charges.

The penalties for a dui are different from state to state. For example in Alabama the driver can be arrested if the officer even thinks that he or she is under the influence. You don't even have to be driving, if you are in control of the car, even without it moving you can be arrested.

The penalties are varied from state to state and include fines, possible house arrest, random drug testing, misdemenor charges, community service, alcohol education and treatment, ignition interlock devices, not being able to attend places that serve alcohol, loss of your license and of course, jail time.

In many states it's virtually impossible to get car insurance after a DUI for several years after a conviction.

If you are facing possible DUI charges the first thing to do is contact a lawyer immediately. A qualified, DUI attorney will know what actions you should take and advise you what to do.