Be sure to find out what make, model and year of car the cop was driving and wether or not it was outfitted with a Genesis radar gun. They are defective and will clock a rock at 70 MPH, according to the report below in the Philadelphia Daily News.
Nearly every cop car in America is a Ford Crown Vic and The Genesis radar gun is also very widely used.
http://www.philly.com/mld/philly/news/local/8139713.htm