Something on the back of your car, that using a combination of your speed, the distance between you and the car behind you, an understanding of the weight of bo

Something on the back of your car, that using a combination of your speed, the distance between you and the car behind you, an understanding of the weight of both cars (using a lookup on the Reg), and the stopping distance, taking into account weather.. is able to calculate the likelihood that the car will crash into you if you slammed on your breaks And then display that figure in a big lcd panel in your back window. Haven’t done it, because every time I remember it, I’m driving my car and forget by time I’m home.