Is a dog sniff during a routine traffic stop considered a search?

The perspective that a dog sniff during a routine traffic stop is not considered a search if the stop is not extended beyond issuing a ticket is grounded in the principles established by the U.S. Supreme Court. The case of Illinois v. Caballes clarified that a dog sniff is not a search within the Fourth Amendment's meaning, as it does not involve any physical intrusion into a person's property nor does it divulge information that is not otherwise available to law enforcement.

The key factor here is the timing and scope of the traffic stop. As long as the traffic stop remains within the confines of its original purpose—issuing a ticket—and does not involve undue delay or prolongation for the purpose of conducting the dog sniff, then it is deemed lawful. The sniff itself is a non-intrusive procedure that is akin to using an officer's sense of smell to detect contraband, and thus does not require a warrant.

In situations where the stop is extended for the purpose of conducting a dog sniff without reasonable suspicion or probable cause, that could lead to it being classified as an unlawful search. Therefore, B is correct as it emphasizes that the legality hinges on whether the original purpose of the stop has been adhered to without unnecessary delay.