Beating the bobbies

Trapster is a mobile application that relies on its community to alert users as they approach a speed trap.

Trapster's userbase is able to give warning by pushing a button or calling a toll free number when they find a speed trap, reports Wikinomics.

Trapster is free to use and works best with phones that support GPS or WiFi.

Trapster also provides an API for connected GPS devices and a Google Maps mashup that shows speed traps, which they call the "Trapplet."