In most drunk driving cases a witness is needed to testify that the person was observed driving the vehicle and that they were intoxicated. However, when the person was not driving the vehicle but was an occupant and intoxicated, court's differ on whether or not the person was "in control" of the vehicle. It is not a matter of whether you were driving the car or not, the test is whether or not you had physical control of the vehicle. For example:
1. In State v. Dey (Mo. Appellate Ct. 1990) The defendant was found sitting behind the wheel of the vehicle but was asleep, but the engine was running. Defendant was convicted.
2. In State v. Hines ( Iowa App. Ct. 1991) The defendant turned the ignition of the vehicle on but did not drive off. Defendant was convicted.
3. In Stevenson v. City of Falls Church ( Sup. Ct. of Vir. 1992) Defendant was sitting behind the wheel but the key was in the off position. Defendant was acquitted.
Criminal Law/Gardner/p. 492
The only way legally get you for DUI is if the motor is running, if the keys are in the ignition and your sitting in the drivers seat. I know someone that passed out in the drivers seat of his car and the keys were not in the ignition. The police tried to charge him with a DUI but he got a lawyer and beat the charge because the keys were not in arms reach to him at all.