Since most SUVs spend time on paved freeways at speed, all these combined aerodynamic debits add up to significantly increased energy required to push air out of the way. A particular variant of the Range Rover offers air springs whereby the ride height of the vehicle could be adjusted depending on its current mission. Using slightly more advanced technology like this would mean that a SUV could potentially excel both on and off road, but the market has shown very little appetite for excellence of this sort. A cab and a bed is then installed on top of this frame. A biological analogy to this design is a vertebrate such as a human being, where the skeleton is concealed inside the exterior surfaces.
Modern cars use unit bodies, also called unibodies or monocoques.
Monocoque design came directly from the aircraft industry where low weight is considered paramount. Quite simply, there is no ladder frame. The entire skin of the car is a stress bearing structure. A biological analogy is the invertebrate such as a crab where the outer shell forms the structure. The advantage of a monocoque in car design is that sheet metal used to form the car's shape is also used as its structure.