Patent ID: 7449998

Claim:
A display unit system for displaying messages, the display unit system comprising: display panels configured to display messages provided by a computing device, wherein the messages include a set of advertising messages including location-based messages, and the display panels are mounted on top of a vehicle and face oppositely from each other so that the messages can be readily seen when the vehicle goes around; a power management unit configured to automatically stop the vehicle energizing the display unit in an event that the vehicle stops for a predefined period; a Global Positioning System (GPS) determining a location of the vehicle, wherein the computing device, coupled to the GPS, communicates wirelessly with a base station to receive at least some of the messages in accordance with the location of the vehicle; and two display plates facing oppositely from each other and integrated orthogonally with the display panels for displaying a default message in a normal condition and activated to display a predetermined message where the default message was displayed when the driver deems it necessary to draw attention from others.