A passenger in a vehicle that is stopped without reasonable suspicion may challenge the unlawful stop under the Fourth Amendment. When the defendant moved to suppress evidence prior to trial, the trial court found that he could not bring the motion because as a passenger he was not detained. The Court of Appeal reversed, partially disavowing its prior holding in People v. Cartright (1999) 72 Cal.App.4th, in which it had held that a passenger has no expectation of privacy and thus may not challenge an unlawful traffic stop. In the instant case, the court held that a traffic stop constitutes at least a momentary seizure of everyone in the vehicle, and that a passenger may consequently challenge an unlawful stop. One justice dissented.