NMA Speed Traps Fact Sheet ( PDF )
Free to download, print & distribute.

When most people think about speed traps, they think about police hiding behind billboards or waiting to pick off motorists right where the speed limit changes.

However, there is a broader, more accurate definition that covers these situations and more:

A speed trap exists wherever traffic enforcement is focused on extracting revenue from drivers instead of improving safety, made possible by speed limits posted below the prevailing flow of traffic.