A method of calculating at least one dimension of a towed vehicle includes sensing an image of the towed vehicle with an image sensing device. A feature on the towed vehicle in the sensed image of the towed vehicle is identified with a controller using a dimension determination algorithm. The dimension of the towed vehicle is determined from the identified feature of the towed vehicle, with the controller using the dimension determination algorithm. The dimension of the towed vehicle may be input into a vehicle tow controller, to enable the vehicle tow controller to control the tow vehicle.