every 5 KM's ,.. this is a joke right?? maybe it would be easier to hang a radar above each car...or install some kind of chip in it.
in our project in RasLaffan, they installed what's called IVMS. which is limiting your speed to 120 max and will beep in very loud if you exceed that and it will record it.it's a solution.

but you need to speed some times,..right?