Automobiles used to be made to be as rigid as possible whereas today they are made to crumple on impact. Why?

Answer 1

Automobile engineers realized that the kinetic energy of the vehicle and its contents had to go somewhere on impact. In old, rigid body designs, that energy had only one place to go -- directly into the bodies of the unfortunate occupants, resulting in hideous injuries. Now car bodies are designed with crumple zones that absorb the energy of impact, thereby sparing the precious and delicate human cargo.

Answer 2

Consider this. If the occupants of the older, heavier, and much stiffer cars wore their seat belts, many of the injuries would have been prevented. Many of the injuries in older cars were due to impact with the stiff interior components of the older car. Wear your seat belts!

Today's cars are so flimsy that even low speed crashes frequently result in injury. Crush zones are the response of the car companies to the danger of driveing one of these little death traps. The cars have no mass with which to resist the intrusion of external forces and parts into the passenger compartment. Air bags have helped, but are not the full answer. They are absolutely no good at stopping a larger bumper, or the car's own engine, from coming into the cab with the occupants.

Give me a old heavy car with seat belts anytime. I have seen many injuries that could have been prevented by seat belt use in a heavy car. I believe the safest car ever built was something like the '56 Olds, if the seat belts were worn. Those things can drive through a Toyota and still drive home. Even today's larger cars are much safer than the little foreign jobs that fold up when hit.

Answer 3

Cars are made lighter to save gas.

Lighter means less stiff, since there is less metal (no heavy frame anymore).

Without the frame, there has to be another way to protect the passengers upon impact, so the car is designed to absorb energy by crumpling around the occupants.