CarTact, released on the Google play store, uses Vehicle license plate number to allow users interaction.
The App Idea is to have users send instant messages to License plate numbers and have the message delivered to all users who have registered the plate number on the App. A user can register multiple license numbers to receive instant messages delivered to those numbers. Any user can register any vehicle number to receive alerts for that number. The App is country specific hence eliminating the likely hood of a message sent to a US car ending up been delivered to a Norwegian Driver.
Messages that can be sent are predefined and Car related. Some predefined messages allows sending of additional text of up to 32 characters, this behavior is intended for sending of Parking Tickets to cars, and Tickets for traffic offence.
You can try out the App, CarTact, by searching for it on the Google Play Store or using this link http://play.google.com/store/apps/details?id=com.uponyishi.cartact
An App that uses Vehicle numbers to contact Owners | Heykuki News