“When police make a traffic stop, a passenger in the car, like the driver, is seized for Fourth Amendment purposes and so may challenge the stop’s constitutionality.”
Justice David Souter writing for a unanimous Supreme Court as reported in The New York Times.
The Washington Post has the better summary of the case and decision.
California had argued that during a traffic stop only the driver was the target of the stop and a passenger “would feel free to depart or otherwise to conduct his or her affairs as though the police were not present.”
[NewMexiKen is trying to picture a car pulled over by the police and the passenger getting out and strolling off. My imagination isn’t up to that challenge.]
“Writing for a unanimous court, Justice David H. Souter ruled that ‘a traffic stop necessarily curtails the travel a passenger has chosen just as much as it halts the driver. . . .’ He said a ‘a sensible person would not expect a police officer to allow people to come and go freely’ from the scene of a stop.”