The Carroll doctrine is a principle, according to which police officers are allowed to search a vehicle without having a warrant if they have a reason to believe it necessary.
In most cases, a policeman needs the warrant to search, but there are a few exceptions. One of them has to do with searching for vehicles and originated back in the prohibition era. This exception is referred to as the Carroll doctrine or the Automobile exception. This legal principle takes its name from the Carroll v. United States case, which took place in 1925. The trial was held because the police had found sixty-nine quarts of whiskey and gin in George Carroll’s car, which was, of course, illegal during the prohibition era. The contraband was discovered by a police officer in the upholstery of the back seat of his car. The search was done without a search warrant.
During court, it was established, that the warrantless search was not unlawful and did not violate the Fourth Amendment, which established the rules of search. Since then, the Carroll doctrine has been guiding police officers on warrantless searches of vehicles, if they had reason to believe that criminal evidence or contraband could be found there. This exception has two reasons, first being the impracticality of getting a warrant because of the vehicle’s mobility because a vehicle can be easily moved from the location of the jurisdiction of the warrant’s validity. The second reason is based on the fact that vehicles tend to be less private. Therefore, the owner does not have as many personal objects, which he would want to protect.
However, there are several Carroll Doctrine requirements for the warrantless search. Firstly, the policeman must have a probable cause for the search, which can be based on some information from a reputable source, or observation of the vehicle. Secondly, the vehicle should be possibly mobile, which means that it can be capable of movement around the time of the search.