I recently launched a new project called PushControl – www.pushcontrol.be . Basicly what it does is sending out (free) notifications to users with information on police controls in Belgium, based on their keywords.
Because PushControl uses push notifications via Notifo and Pushover (php class) next to sms, email and twitter notifications,almost everyone will be able to receive notifications. Even folks with a Nokia 3210 (do they still exist?)! Signup is free via Facebook. PushControl is actually a facebook app / mobile webapp (responsive) / normale website.