[jessedhillon]

IANAL either.

However, in South Dakota v. Opperman (http://supreme.justia.com/us/428/364/case.html) the court upheld that police may search and inventory a car without a warrant, even though the car was impounded for parking violations and not on suspicion of drug offenses (as it turned out was the case). I would conclude, therefore, that a car impounded during an arrest can definitely be searched.