Honda Car Forum

what kind of material is used on the exterior of Japanese vehicles why is it so thin and cheap?

That's the way they've always been. They use thinner gauge steel to save money - less steel, less cost. One benefit is that the car is made lighter and gets better mileage. The problem is that it gets dinged easier and is less safe.

usually the fiberglass

It has nothing to do with safety. It is usually either steel or polyurethane. But japanese cars are way safer because of the engineering of the car. Just because a piece of metal is thinner or bends more easily in a parking lot crash, it doesn't have any bearing on the actual ability of the crash structure to handle loads. All car manufacturers do lots and lots of FEA- Finite Element Analysis so they can engineer the car's safety as a whole rather than by component. As a result, cars are safer now than they've ever been.It's simple physics, deforming a structure absorbs energy which could otherwise be transmitted to the occupants. If you had an indestructible car, it would be LESS safe in a 30 mph crash because all the decelerative loads get transmitted directly to the passengers. Stopping in 2 feet is much better than stopping in 0 feet.