This is for cars or, more importantly, pedestrians in a parking lot, for example, who are coming up on the car from the side and visibility in in limited. Once they are behind the car, it can be too late to stop. Many cars have this now and typically relies on side radar from the rear of the car.Does Model X not beep at you if there is a car or pedestrian approaching when the X is backing up? I would be disappointed if that is the case.