Different Types of Body Structure

One-Box design

It is widely believed that one-box design offers the biggest interior space for a given external dimensions. However, I always doubt its effectiveness. Compare with conventional two-box hatchback, one box car frees up the space in front of the driver by pushing the windscreen forward. Nevertheless, as shown in the above drawing, such additional room (grey area) does not really contribute to driver's comfort. It just create a "freer" feel to the driver.

Because the windscreen is pushed forward, visibility is actually deteriorated, as shown in the drawing. The driver even cannot see the front end of his car, thus made arise some problems for parking.

Cab-foward design

	Push the front-wheels towards the corners, shorten the engine compartment, move the windshield forward so that its base rests near the front wheels, this is the so-called "Cab-foward" design. Chrysler tells us Cab-foward design frees up the room for front passengers....
	.... this is right when compare with long-nose traditional American cars ....
	....but when compare with any standard European cars, Chrysler's cabin seems to be not so Forward.

Sandwich Structure - Mercedes A-Class

This stucture is called "Sandwich" because the horizontal-orientated engine is placed above the floorpan but under the cabin. As a result, the cabin is raised by a massive 200 mm and so is the roof. What is the advantage of such structure ? Firstly, because of the disappearance of the front engine compartment, it made the car more compact than any other cars but simultaneously offers class-leading cabin space (actually runs close to C class).

Secondly, it provides exceptional crash-protection. Under crash, the engine will be pushed underneath the cabin instead of pushed towards the driver's legs as conventional cars. Therefore A class will pass any foreseeable crash test in the future. Thirdly, due to the inherent advantage in crash-protection, no additional crash structure is needed, thus a lot of weight is saved.