A trailer based collision warning system includes one or more side object detection sensors, one or more backup assist sensors, a driver vehicle interface, and trailer-mounted display units operating essentially independent of the tractor with all detection and warning system equipment mounted on the trailer. The trailer based collision warning system is coupled to industry-standard tractor to trailer wiring to provide the trailer with power and signals such as left turn indication and right turn indication. The side and rear sensors detect the presence and location of objects and transfer this information to a driver vehicle interface device located on the trailer. The system can also be equipped with video cameras with a means of automatically activating the camera in the area where a hazard condition has been detected. The driver vehicle interface determines the nature of the information and/or warning needed by the driver and provides this information in the form of signals sent to displays that can to assist the driver in safely maneuvering the trailer. The collision warning system can also operate in a security mode.