The weight of the car is distributed over the area of the frame. This frame makes the car much lighter and, as a result, more fuel-efficient. These frames are still used in mid-sized cars and some large cars. This frame encompasses the entire car including the roof. These frames are designed to crush in select areas called crumple zones to absorb the impact of a collision.
Engineers claim that they are much safer then other frames.
All through these changes, light trucks continued to be built with full frames. In a collision between SUVs and cars, the SUVs frame doesn't flex or crush as much as the cars do. This causes the car to collapse as it tries to absorb the impact for both vehicles. It seems that cars have become more dangerous over the years. The main problems in collisions between SUVs and cars are the weight and height differences.