Which type of vehicle frame is used for most modern passenger cars?

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

Answer: (B)

Unibody construction is what most modern passenger cars use because the body and the frame are built as a single integrated structure. This design makes the entire vehicle act as one rigid shell, which provides several practical advantages. It reduces weight compared with a separate body and frame, which helps with fuel efficiency and handling. It also improves safety by allowing engineers to design crumple zones that absorb crash energy while keeping the passenger compartment intact, and it increases overall stiffness without needing a heavy, separate chassis.

In contrast, body-on-frame designs keep the body mounted on a separate ladder-like frame, which tends to be heavier and is more common in trucks and some older vehicles. A ladder frame is basically a strong backbone but doesn’t provide the same efficiency or crash management as unibody. Space-frame designs use a network of tubes for rigidity but are not used for the vast majority of mass-market passenger cars. Therefore, unibody is the standard choice for most modern passenger cars.