You only need to look at what happens to a W in a car ahead collision, IIRC when an A class ran into the back of a W on Victoria Pde several years ago, the A barely had any damage while the W's cab was pushed half way in (even the bumper had the inverse shape of an A class bumper). If the roles were reversed and the W had been the aggressor instead, the driver of the W probably would have been trapped under the controls when the cab got squished. Also note that most car ahead collisions happen at only 5-20 km/h after the driver has dropped the anchors yet the poor old W still folds up in a heap upon impact.