Do I have to let the police search my vehicle?
No. The United State Constitution and New Jersey Constitution, under the Fourth Amendment, can deny the police the right to search you care without a search warrant. But understand, that by refusing to consent to search the vehicle, the police can seek a search warrant from a court of law. That means that the vehicle can be held for a reasonable amount of time in order to get a search warrant.
Article I, Paragraph 7 of the New Jersey Constitution provides:
The right of the people to be secure in their persons, houses, papers, and effects, against unreasonable searches and seizures, shall not be violated; and no warrant shall issue except upon probable cause, supported by oath or affirmation, and particularly describing the place to be searched and the papers and things to be seized.
However, under certain exceptions to the search warrant requirement, police can search your car without a warrant. The automobile exception to the warrant requirement -- as defined by the United States Supreme Court in construing the Fourth Amendment -- authorizes a police officer to conduct a warrantless search of a motor vehicle if it is readily mobile and the officer has probable cause to believe that the vehicle contains contraband or evidence of an offense.
The New Jersey Supreme Court issued a ruling in late September 2015, State v. Witt, 223 N.J. 409, 447 (2015). regarding the circumstances in which police can search a vehicle without a warrant during a traffic stop. After arresting the defendant on suspicion of driving while intoxicated (DWI), the arresting officer searched the vehicle and found a handgun. This resulted in a charge of unlawful possession of a firearm. The court found that the search was lawful, despite the lack of a warrant. According to the court, "This exception authorizes a law enforcement officer to conduct a warrantless on-scene search of a motor vehicle only when there is probable cause to believe the vehicle contains contraband or evidence of an offense, and circumstances giving rise to this probable cause are "unforeseeable and spontaneous."
Search incident to arrest is another excepton to the warrant requirement. Under Federal Law, once an police officer determines that there is probable cause to make an arrest, it is reasonable to allow officers to ensure their safety and to preserve evidence by searching the entire passenger compartment. Under New Jersey law, a warrantless search of an automobile based not on probable cause but solely on the arrest of a person unable to endanger the police or destroy evidence cannot be justified under any exception to the warrant requirement and is unreasonable. In State v. Eckel, the Supreme Court of New Jersey held," once the occupant of a vehicle has been arrested, removed and secured elsewhere, the considerations informing the search incident to arrest exception are absent and the exception is inapplicable".
The final exception is a protective sweep of a vehicle. Law enforcement can perform a warrantless search of the passenger compartment of a vehicle when the totality of circumstances supports a reasonable suspicion a driver or passenger is dangerous and may gain immediate access to weapons. State v. Gamble, 218 N.J. 412, 431-32 (2014)