How do you explain this...

Are cars so soft that the roof will collapse just from jumping on it, and the doors will twist and pop open just by kicking them. These youtube vids show people demolishing cars like they were made of paper. Are cars just generally poorly made these days or is there some other aspect that I'm not seeing? Any thoughts would be appreciated.

http://www.youtube.com/watch?v=4Csxh-78FL8

http://www.youtube.com/watch?v=vz3yUOPOUCg

Well Im not sure what you mean by "these days" as both of the cars in the videos seemed rather aged to me. While im not an expert on how cars are made, I know that it is more in the interior of the body (not the shell, but the steel and reinforments under it). Your seatbelt does alot of work too.

Unregistered said:

Are cars so soft that the roof will collapse just from jumping on it, and the doors will twist and pop open just by kicking them. These youtube vids show people demolishing cars like they were made of paper. Are cars just generally poorly made these days or is there some other aspect that I'm not seeing? Any thoughts would be appreciated.

http://www.youtube.com/watch?v=4Csxh-78FL8

http://www.youtube.com/watch?v=vz3yUOPOUCg

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Yeah, that's about how it is. Those are older and probably don't have reinforced safety cages like most cars do now, but still you WANT your car to 'give' a little (what I mean is, yes, the outer parts of the car SHOULD be easy to destroy), so it absorbs energy in a crash instead of transferring that energy to your body. I'm a little annoyed with cars whose bumpers are only for 'looks' and when you bump them into things it can cost thousands of dollars to fix (www.iihs.org has bumper ratings from time to time, it may be on their site all the time).

sheet metal is *much* thinner "these days", that is for certain!

BUT, cars are so much more safe in a crash, even without technological innovations like airbags. cars today are built around the "Safety cage" concept, where the entire passenger compartment is built to withstand deformation after the most common type of impacts, while sections fore and aft of the passenger compartment are designed to deform and absorb energy during a crash. the structural strength of teh safety cage comes not from the body panels that you see, like the roof skin, door skins, hood and fenders, but from the unibody frame components underneath. some years ago, IIHS did a side by side crash test with a toyota camry. one was a "normal" car, the other had the front bumper skin, hood, and fender removed. the car's skeleton was completely exposed. after the crash, theyh removed the panels from the normal car, and the crumpled front region and passenger compartment region appeard the same in both cars.

also interestingly, despite sheet metal getting thinner, cars keep growing in weight, reflecting the heavier substructures and frame elements that contribute to the increased safety of newer cars.

Vehicle roof strength standards have remained unchanged for several decades if I remember right, kind of scary to contemplate given the higher percentage of SUVS/trucks/vans on the road with a greater potential for rollovers.

Thanks or the replies. Does it look like the rear door of the station wagon in the first clip had popped open? I understand that a vehicle's frame is the most important aspect of collision safety, but wouldn't it be beneficial for the structural integrity in a crash for the doors to stay shut. Do you think it is possible to kick open a car door? Or are they designed to be able to withstand a great deal of force and impact before they open.

And one last question, does anyone know if newer cars have cross beams between the roof pillars to keep the roof skin from caving in and protruding into the passenger compartment.

Before the IIHS started to really press automakers to use the "safety cage" design, there was a problem with many automakers not using strong enough steel. Cars were a lot less safe. I believe that Mercedes Benz pioneered the safety cage design in commercial automobiles and it is not integrated into all cars. I wouldn't be as concerned about the outer shell of a car compared to the cage. Back when the Lexus first came out, they used really weak steel on the outside of their cars. You could push the roof down enough with just your hand and slide things in the care through the sunroof. To me that was pretty scary. Also, their seats were made with very week steel and they had a problem with people submarining out of them in accidents. I also heard reports of Honda Accords from the 90's falling off the assembly line b/c the contact points that held them in the air were too weak. This may have been a rumor. Anyway, my real point is that the outside metal of today's cars maybe less strong but the safety cages are designed much better.

Side said:

Thanks or the replies. Does it look like the rear door of the station wagon in the first clip had popped open? I understand that a vehicle's frame is the most important aspect of collision safety, but wouldn't it be beneficial for the structural integrity in a crash for the doors to stay shut. Do you think it is possible to kick open a car door? Or are they designed to be able to withstand a great deal of force and impact before they open.

And one last question, does anyone know if newer cars have cross beams between the roof pillars to keep the roof skin from caving in and protruding into the passenger compartment.

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i didn't see the video, so i can't comment on the door popping open, but i know that there is supposed to be *some* resistance to openining upon a side impact. i don't know if and how it is written into DMV standards, but i remember reading somewhere that there were some standards in that regard.

as for the roof cross beams, yes, there are some beams (i used to install aftermarket sunroofs when i was an installer years ago and had to cut into roofs, so that's how i know this), but i don't know to what standards they are designed; i.e., whether they are designed for actual intrusion resistance in a rollover, or to just keep the sheet metal from buckling from something trivial like heavy snow or ice.