A blind spot warning method is disclosed for a tow vehicle. The method includes determining whether a trailer is connected to the tow vehicle. Based on the determination whether the trailer is connected to the tow vehicle, the determines whether a blind spot zone corresponds to the tow vehicle or to the tow vehicle and the trailer. At least one instruction is sent to a user interface of the tow vehicle for displaying an image for viewing by a driver of the tow vehicle. The displayed image indicates the determination whether the blind spot zone corresponds to the tow vehicle or to the tow vehicle and the trailer, and indicates a presence or absence of at least one other vehicle disposed in the blind spot zone.