The United States Supreme Court has extended to vehicle passengers the same constitutional protections that are now afforded to vehicle drivers.
The United States Supreme Court ruled that a driver and his passengers have been seized from the moment a vehicle car had been halted on the side of the road, and that it was egregious judicial mistake for the California trial court and for the California Appellate Courts to deny the defendant's motion to suppress the evidence seized after being stopped by law enforcement on the mere ground that seizure [of the arrestee] occurs only after a formal arrest.
The law had long been recognized that the driver of a vehicle who has been pulled over is "seized at the moment he submits to an officer's show of authority by pulling his vehicle to the side of the road", but the Supreme Court had not ruled on whether passengers in the same vehicle have the same protections as the driver.
In this case, Brendlin vs. California, law enforcement officers stopped the arrestee's vehicle without good probable cause. An officer recognized the passenger, but could not remember whether he had escaped parole. After ordering the driver out of the vehicle, officers searched him and the vehicle. The police found items used to manufacture drugs.
The arrestee was charged with and convicted of possession and manufacture of the controlled substance. In the California state trial court proceedings, the judge had refused to suppress the evidence, saying that the defendant had not been seized until he was ordered out of the car. The defendant's criminal defense attorney had argued unsuccessfully at the trial court level that the driver and his passengers were seized for Fourth Amendment purposes when the car was pulled over without reasonable suspicion, requiring suppression of the evidence.
The State Supreme Court upheld the trial court, asserting the absurd contention that a passenger in a vehicle pulled over by the police would feel free to depart or otherwise to conduct his or her affairs as though the police were not present.
When the case was considered by the United States Supreme Court, Justice Souter wrote the unanimous Opinion. He said that a seizure occurs if in view of all of the circumstances surrounding the incident, a reasonable person would have believed that he was not free to leave. A reasonable passenger, during a traffic stop, would not believe he was free to leave without police permission. A passenger will expect to be subject to some scrutiny, and his attempt to leave the scene would be so obviously likely to prompt an objection from the officer that no passenger would feel free to leave. A passenger should also expect an officer to forbid people from moving around in ways that could jeopardize his safety.
The Supreme Court had already ruled in that an officer may order a passenger out of the car as a precautionary measure, without reasonable suspicion that the passenger poses a risk. The risk of harm to both the police and the occupants is minimized if the officers routinely exercise unquestioned command of the situation.
Thus, search and seizure protections have now been applied to the passengers of a vehicle stopped without probable cause.