Vehicle park assist systems and a method of operating a vehicle including an operably attached trailer. The vehicle park assist system includes a transmitter arrangement to produce incident energy on an obstacle, and a sensor arrangement to detect reflected energy from the obstacle. A controller determines an obstacle status based on the reflected energy, and detects attachment of a trailer to the vehicle. A warning apparatus operably coupled to the controller indicates the obstacle status. The warning apparatus is regulated based on the attachment of the trailer to the vehicle. The method includes providing a vehicle park assist system, detecting the attachment of the trailer to the vehicle, and regulating the vehicle park assist system based on the attachment of the trailer to the vehicle.