In modern vehicles, what construction method means the frame and body are integrated?

• A. Hardbody
• B. Unibody
• C. Body-on-frame
• D. Ladder frame

Answer: (B)

Unibody construction means the frame and body are integrated into a single rigid shell. The load paths from the suspension and body panels share the same structure, so there isn’t a separate skeleton that the body sits on. This integration is why most modern passenger cars are built this way: it reduces weight, improves efficiency, and provides better crash energy management by blending the body and chassis into one continuous shell.

In contrast, body-on-frame designs keep a separate, strong frame under the body. The body is mounted on this frame, which is common in many trucks and some larger SUVs because it handles heavy loads and off-road forces well. A ladder frame is a specific type of body-on-frame construction consisting of two long rails with crossmembers, not a single integrated unit. The term hardbody isn’t used to describe the integrated structure and doesn’t indicate this single-shell construction.