Today the United States Supreme Court issued a unanimous opinion concerning the rights of car passengers to assert Fourth Amendment challenges when a police officer initiates a traffic stop:
When a police officer makes a traffic stop, the driver of the car is seized within the meaning of the Fourth Amendment. The question in this case is whether the same is true of a passenger. We hold that a passenger is seized as well and so may challenge the constitutionality of the stop.
Brendlin v. California (No. 06-8120) 38 Cal. 4th 1107, 136 P. 3d 845, vacated and remanded.