A vehicle on-board unit of a host vehicle is configured to communicate with other vehicle to alert the driver of a potential braking situation in a preceding vehicle. The vehicle on-board unit has an incoming message receiving section, an incoming message relevancy section and a driver warning section. The incoming message receiving section receives a preceding vehicle message containing throttle release data of a preceding vehicle located in front of the host vehicle. The incoming message relevancy section performs a relevancy determination of the throttle release data received. The driver warning section selectively alerts a driver of the host vehicle of a potential braking situation of the preceding vehicle based upon the relevancy determination.