lietuviai,

There is an excellent book that talks about this called "High and Mighty: SUVs : the world's most dangerous vehicles and how they got that way" by Keith Bradsher. Bradsher talks about how vehicles react in side impact collisions and why cars don't do so well against non-cars. Bradsher says that as long a the bumper of one vehicle matches up with the lowest part of the door on the other vehicle, the side energy is tranfered into the floor and that provides the safety. This works well between most cars because the bumber height is about the same as the floor height at the side. Trucks and SUVs don't need to follow the same bumper height restrictions that cars do, so thats where the problem lies. I think they can be as high as 54" but I'm not sure.

So SUVs and truck bumper heights are not required to match car bumber heights or floor heights. They can also intall battering rams like bull bars and winches on the front. So no matter what kind of side impact designs that one can dream up for cars, they aren't going to work properly against something like SUVs or trucks.

SUVs and trucks aren't regulated like cars are for emissions, fuel economy, safety, etc. To improve side impact safety, we need to standardise the bumper heights first, then dream up newer and better designs. Or ditch our cars and buy SUVs or trucks so that our floor height is the same as the next guys bumper.