Patent ID: 7378948

Claim:
A digital message display for vehicles comprising: a message display capable of displaying short textual messages; at least one short range distance sensor having a first sensing range, the at least one short range distance sensor being adapted for mounting to a rear surface of a vehicle; at least one long range distance sensor having a second sensing range, the second sensing range being greater than the first sensing range, the at least one long range distance sensor being adapted for mounting to the rear surface of the vehicle; a microcomputer in electrical connection with said message display and with said at least one vehicle distance sensor; and a computer readable program code contained in said microcomputer, the program code having means for selectively reading a trailing vehicle distance from either of said at least one short range distance sensor or said at least one long range distance sensor, means for determining when the trailing vehicle distance falls below a safety threshold, and means for selectively displaying on said message display one of a plurality of predefined short textual messages when the trailing vehicle distance falls below said safety threshold.