DWI (Driving While Impaired) is slightly different from driving under the influence because in many states of the US DUI refers only to driving under the influence of alcohol and or narcotics. But Driving While Impaired may mean the driver’s judgement may be impaired by many reasons such as illegal narcotics, alcohol or even prescription drugs that interfere with his/her driving ability.

In the United States, DWI (Driving While Intoxicated or Driving While Impaired) are primarily crimes associated with driving motor vehicles. They consist of the following two segments:

Administrative component

This segment of the crime of drunk driving comes under the purview of the Department of Motor Vehicles and it commences only when a law enforcement officer (LEO) suspects a driver of being under influence of a driving ability impairing substance.

The police officer than has the legal right to ask him (or her as the case may be) to give, blood, breath or even samples of urine to determine the quantity of any narcotic in the bloodstream.

While the driver would be well within his legal rights to refuse such (potentially invasive testing,) however such a refusal may well result in an automatic suspension of his driving license in most constituent states of the US.

This is because the acquisition of a driving license is implied consent (or voluntary agreement) of the license holder to allow him to be tested as and when called upon by an LEO.

Since the drivers voluntarily agree to chemical testing whenever called upon by the representatives of state authority if they are suspected of violating DWI laws. Therefore refusal to comply with something that they had agreed to already when given the license,  would effectively mean the forfeiture of all driving permissions  granted to the driver courtesy the suspension or even cancellation of his license.

Such an individual is not authorized to drive a motor vehicle until his suspension (or cancellation) is revoked by the concerned authority.

Criminal component

If a driver is convicted of DWI then he would have to undergo criminal penalties such as (mandatory) jail time along with stiff fines and/or community service.