mobile information system preventive compliance speeds.

The invention relates to a mobile device velocity detecting and identifying land vehicles consisting of a carriage (1) on which are arranged a speed sensor (101) and a camera (103). When a vehicle (3) exceeds a predefined threshold, the camera (103) acquires an image and deriving means (104) extracts and recognize the license plate number of the vehicle (3). The camera (103) and the speed detector (101) are mounted on a pole of a height of between 2m and 3m, which can be folded to reduce the size of the device during transport and storage. The invention also relates to a vehicle detection system for the display of their speed and their registration number, comprising such a mobile device detection and identification (1) and at least one variable message sign ( 2), used mainly as a preventive measure, to encourage motorists to respect speed limits in correspondence road works.