Search warrants are generally required when police officers search your property -- unless a specific exception applies. In 1925, the U.S. Supreme Court carved out a major exception to the search warrant requirement in a case called Carroll v. United States. It created the "automobile exception" or "motor vehicle exception," which essentially allows any motor vehicle to be searched without a warrant as long as the officer has probable cause to believe that evidence or contraband will be found in that vehicle.
An influential federal appeals court has ruled that a judge erred when granting a search warrant for a cellphone. That search warrant granted police the authority to search a man's residence for any cellphones or electronic devices he might own, and the court said the warrant was unconstitutionally vague.
When are police officers allowed to search your glove box after a traffic stop or an accident? At its base, it's a civil rights issue. The Fourth Amendment of the United States Constitution prohibits "unreasonable searches and seizures" by government agents such as police.