Which type of vehicle structure absorbs impact through crumble zones?

The type of vehicle structure that absorbs impact through crumble zones is the unitized or unibody frame. This design incorporates the vehicle's body and frame into a single cohesive structure, allowing for efficient energy absorption in the event of a collision.

The crumble zones are specifically engineered areas that deform and crumple upon impact, dissipating energy that would otherwise be transmitted to the occupants of the vehicle. This safety feature significantly enhances the protection provided to the passengers in a crash by reducing the force experienced inside the cabin.

In contrast, other vehicle structures such as the conventional full frame and semi-monocoque structure may not feature the same integrated impact absorption capabilities. The chassis cab design typically refers to a type of vehicle intended for specific uses like trucks, which may not prioritize the same safety features compared to the unibody design. Therefore, the unique characteristics of the unitized or unibody frame make it the correct answer for this question.