What is the current state of the law on the right to search a vehicle without a warrant?

It is unfortunately too common an occurrence in current times that a person told to remove himself from a place because of his intoxicated condition will go home and return with a firearm to inflict harm upon one who told him to leave. Likewise, it is becoming too common an occurrence where police officers investigating a crime get shot by a shotgun secreted or carried in a motor vehicle. The only choices open to the officers here were to make a search of the vehicle without a warrant or else impound it while obtaining a search warrant. Under circumstances here presented, Chambers v. Maroney, Supra, justifies the immediate search without a warrant, although it should be limited to just that area where the officer had reasonable and probable cause to believe that he would find a weapon and to the single purpose of ascertaining whether there is a weapon. If in the course of making this protective search, it develops that there is reasonable and probable cause to believe that a misdemeanor is being committed in his presence or that a felony is or has been committed, he may then arrest the suspect without a warrant. The search for the weapon was for the dual purpose of investigating if a crime was being committed and to interdict defendant's possible use of the weapon either against the officers or other persons, including possibly intended victims of violence, in the area. Certainly, the lifting of a hood of a vehicle parked in a public place is less offensive to a defendant's dignity and security than a frisking of his person would have been.