It is not rocket science

and nobody says physics laws should be rewritten. But you can't analyze the situation with sort of one-dimensional input, in this case, size. For example, is the car designed to crumple on a head-on collision? Do you want the car to be damaged (to absorb the energy) or the driver injured? How many airbags are there and how are they positioned? Independent studies have shown the safety design and build quality of cars are critical in determining the outcomes of these car accidents.