Almost all states in the US have the notion of "implied consent" when it comes to issuing driver's licenses. Basically, the concept is that any person who operates a motor vehicle on a roadway automatically gives consent for the state administered chemical tests of one's blood, breathe or urine if the police officer has probable cause to believe that the driver is under the influence of alcohol or drugs. One still has the right to refuse the state administered test, however refusal carries almost the same penalties as an actual DUI conviction (suspension of driver's license, fines, etc). Here in Georgia, the suspect also has the right to request his OWN blood-alcohol content test from a doctor or facility of his own choosing after taking the state-administered test (within reason: one cannot request the test be adminitered at some hospital on the other side of the state).