Justification for motor vehicle stops

It is well settled that the stopping of a motor vehicle and the detention of its occupants constitutes a seizure within the meaning of the Fourth and Fourteenth Amendments to the US Constitution, even though the purpose of the stop is limited and the detention is brief. The United States Supreme Court in Delaware v. Prouse, 440 U.S. 648 (1979), held that the police must have at least an articulable and reasonable suspicion that a violation of the traffic laws has occurred. This may include a reasonable suspicion that the driver is unlicensed, the vehicle is not properly registered, or that an occupant in the vehicle is subject to seizure for a violation of the law. Absent a reasonable and articulable suspicion, individual police officers may not use their unbridled discretion to effect motor vehicle stops. The Prouse case involved a random stop by a police officer to check on a driver’s credentials. There was no justification for the stop other than a desire to perform a random check. Although the Supreme Court ruled that the random aspect of the stop was unreasonable, it did not rule out other types of spot checks by the police. One such suggested stop would be a supervised road block where all vehicles would be stopped and questioned about driving credentials. However, the court was clear that individual officers could not effect motor vehicle stops in the absence of a reasonable and articulable suspicion.