Abstract: An electronic device for being carried on a vehicle for transmitting information to a vehicle following it over a given route. The electronic device is also intended to receive information coming from a vehicle preceding it over the same route. The device includes a transmitter for transmitting information and a chronometric scanner adapted to detect deceleration of the vehicle by comparing speed values communicated to it by sensor. In the event that deceleration values exceed a certain threshold, a signal is sent to a radio transmitter device adapted to transmit a deceleration signal via an antenna on the rear of the vehicle. The electronic device also includes a radio receiver for receiving information from an antenna at the front of the vehicle regarding deceleration of vehicle in front of the vehicle. An alarm device emits a visual and/or audible alarm in the event of sudden deceleration of a vehicle preceding it.