Today, the United States Supreme Court held that the police may use an ordinary traffic stop as a means to seek evidence of crimes unrelated to the pull over.  Justice Ginsburg said that a prolong traffic stop beyond what was needed to deal with the initial offense was improper, even if only for a few minutes.

http://www.policeone.com/drug-interdiction-narcotics/articles/8530149-Justices-Traffic-stop-cannot-be-extended-to-bring-in-K-9

Criminal Defense Attorney Jimmy Cha