I havent tried them on Android yet, but when I was running Windows Mobile, I played around with WAZE (
http://www.waze.com). It's a navigation application with a social media backing. You and other Waze users submit traffic, police traps, etc... and it gives turn by turn directions based on your directions. Even the maps are updated when you drive on new roads. I've used it coming back from upstate NY to Long Island and it's served me well....
You can also check out Trapster (
http://www.trapster.com/) for reporting/notification of Police Traps.
These are the only 2 I know of... I'm sure there's others, possibly based on the traffic system in your area (on Long Island, NY there's INFORM which has web sites where you can watch traffic, cams, etc..)
