A unibody frame is a type of vehicle construction where the both the body of the car and the chassis forms a single unit; reinforcements are then added to other specific sections of the car. Most modern cars are built with unibody frames because they provides better absorption during impact as well as improved structural stability.
The first car manufactured with a unibody frame was the Citroen Traction Avant. Mass production of the car began in 1934. The unibody design slowly became popular after that.
Unibody frames offer several advantages over than body-on-frame builds. They are lighter than body-on-frame builds which helps with fuel economy and handling. Unibody frames also direct kinetic energy with greater efficiency, making them a safer choice for cars.
Many auto makers still use the body-on-frame option for building trucks, because it is better suited to off-road forays. Another benefit is that the in-body design makes it easier to repair of replace worn out parts. It also helps in keeping SUVs grounded. However, there are some trucks that feature the unibody frame. The 2004 Honda Ridgeline marked the first time a truck was designed with a unibody frame. Its success has led to the adoption of unibody frames with several SUV brands, such as the Toyota Highlander and Jeep Grand Cherokee.