Flashing oncoming motorists with your high beams used to be an effective, if low-tech, way to warn them about speed traps up the road. But radar-gun wielding cops have increasingly given way to photo-enforcement cameras that nab drivers with a click of a shutter, and those can be hard to spot.

But now the wonders of Web 2.0 and portable navigation systems can use motorists' tips and Google maps to help keep you from appearing on your local police department's version of candid camera.

Shannon Atkinson launched Njection.com as a place for gearheads to shoot the breeze about anything and everything auto-related. It wasn't long before he sensed a theme in the posts. “One of the biggest topics on the site became speed traps and cameras,”

So Atkinson added Speedtrap, a feature that combines drivers' tips with Google Maps to identify speed traps

Now, the information can be downloaded directly to portable navigation devices from Garmin, Mio, TomTom and others via Njection.com