The United States Supreme Court held that a canine sniff conducted without reasonable, articulable suspicion of criminal activity during a lawful traffic stop did not violate the Fourth Amendment.
Illinois v. Caballes, 125 S. Ct. 834 (2005).
Jennifer M. Palonis,
Canine Sniffs and the Admissibility of Evidence Seized during Lawful Traffic Stops: Illinois v. Caballes,
Duq. L. Rev.
Available at: https://dsc.duq.edu/dlr/vol44/iss1/12