A vehicular backup assistance system includes a rear backup camera for a rear portion of any vehicle family member of a particular family of vehicles that includes a plurality of vehicle configurations, with each vehicle family member of the particular family of vehicles having a vehicle configuration that is different than the vehicle configuration of any other vehicle family member of the particular family of vehicles. A processor and a display are at a vehicle family member having the particular vehicle configuration of the particular family of vehicles. During a reversing maneuver, and based on the wheelbase of the particular vehicle configuration of the particular family of vehicles and based at least in part on a current steering angle of the vehicle family member, the processor generates a predicted vehicle trajectory that is displayed at the display as a dynamic overlay overlaying the images captured by the rear backup camera.