Interestingly, there was a pretty important 4th amendment decision in the US Supreme Court yesterday.
http://reason.com/blog/2015/04/21/supreme-court-says-police-violated-4th-ahttp://www.supremecourt.gov/opinions/14pdf/13-9972_p8k0.pdfCops can no longer make you wait around for a drug sniffing dog to get to a traffic stop unless they have probable cause for doing so. In the case above, cop issued a traffic citation and then made the guy wait for 7ish minutes till the drug sniffing dog got there. Dog found drugs. Court ruled that requiring the defendant to wait after the citation was issued was unconstitutional and the lower court's denial of motion to suppress the evidence was in error.
I don't know how much this will change the reality of such traffic stops since police probable cause is a pretty subjective thing but...it's still a victory for the 4th amendment on paper.
