In what circumstances will the police be permitted to search the passenger compartment of a car after a tip from an informant?

In Adams v. Williams, 407 U.S. 143 [92 S.Ct. 1921, 32 L.Ed.2d 612] (1972), we held that the police, acting on an informant's tip, may reach into the passenger compartment of an automobile to remove a gun from a driver's waistband even where the gun was not apparent to police from outside the car and the police knew of its existence only because of the tip. Again, our decision rested in part on our view of the danger presented to police officers in traffic stop and automobile situations.