Twisted metal at the front and rear of a modern car is not a sign of failure but of design. Those empty looking sections are crumple zones, engineered to fold, tear and collapse so the passenger cell stays almost geometrically unchanged when a crash happens.
The physics is blunt. A moving car carries kinetic energy that must go somewhere during a collision. If the body shell is rigid, the energy transfers into the occupants as extreme deceleration and peak g forces over a very short time. That spike overwhelms the tolerance of organs, especially the brain and aorta, even if the structure hardly bends.
Crumple zones stretch the crash out in space and time. Controlled deformation converts kinetic energy into plastic deformation and heat, extending the impact pulse and lowering peak deceleration. That reduces thoracic compression, lowers the risk of traumatic brain injury and keeps survival rates higher than any tank like body could manage.
Engineers treat the cabin as a survival cell, pairing high strength steels and load paths with sacrificial sections that surrender first. Seatbelts and airbags are tuned to this time history of deceleration. The car dies in stages so that the human body inside is asked to endure forces it can actually survive.
