How long is a search of a vehicle without a warrant valid according to the "carol doctrine"?

The correct answer is based on the principle that as long as law enforcement officers have probable cause to believe that a vehicle contains evidence of a crime, they may conduct a warrantless search of the vehicle. The "Caroll doctrine" (often referencing the case Carroll v. United States) establishes that vehicles are inherently mobile and can be quickly moved out of the jurisdiction, which is why officers are allowed to search without a warrant if probable cause exists at the time of the search.

When probable cause is established, the urgency and the nature of vehicles justify this immediate search to prevent the loss of evidence. This means the search remains valid for the duration that the probable cause is intact; it is not restricted by a set time limit like 30 minutes. Neither the apprehension of the driver nor the indefinite duration applies since once probable cause is determined, the search can proceed.