Speeders - check this out

OFF THE WIRE
Check out this smart phone application. It's called Trapster. It warns you of radar enforcement, and gives you the ability to warn others of radar enforcement ahead.  

http://www.popularmechanics.com/cars/how-to/products/10-handy-smartphone-apps-for-drivers?src=nl&mag=pop&list=nl_pnl_aut_non_020912_smartphone-apps&kw=ist#slide-3