Instinctive jump into the car by police dog (aka: "Jampy") was constitutionally permissible search, as the dog's initial movement towards the car would have justified the search.
http://media.ca8.uscourts.gov/opndir/18/06/171371P.pdf
Since 2011. An occasional commonplacing of the U.S. Circuit Courts of Appeal.
Not written by a barrister. The name was thought up by a second-year American law student sitting in a coffeehouse in Manhattan. Neither an authoritative statement of the law nor legal advice.
Don't rely. Quick work.