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Comment by ansimionescu | Hacker News Reader

In Romanian 'car crash' is called literally 'accident' [0]. Something that's always baffled me is how friggin' thin the metal plates that make up the car are. Why the fuck does a whole industry consider this normal?! [1]

Edit: thanks for the info (and for the downvotes <3)

0: http://translate.google.com/#en/ro/car%20crash

1: http://www.youtube.com/watch?v=qhCXFsQ6kKQ

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Because you WANT it to deform. A stiff structure would increase deceleration on the occupants - in addition to being more likely to get in accident in the first place - additional weight will cause the vehicle to brake less rapidly, be more likely to roll over, etc, in addition to reducing efficiency.

I've often wondered about this. Instead of just having a single thin metal skin that deforms, wouldn't it be even better to have multiple skins sandwiching a kind of honeycomb structure? That way you have even more stuff to deform and absorb the impact.

If there's a way to increase safety, I am sure that they had thought of it.

So you're saying we're at the theoretical optimum of car safety and that there are no possible improvements?

High performance aircraft and cars already do this. They thought of it - and it's expensive.

Right now, you have multiple skins sandwiching air.

You know how the original Volkswagen Bugs had that empty front hood, because the engine was in the rear? My dad advocated filling the front hood with bags full of empty aluminum cans.

The only stuff that actually matters is keeping people from being squashed and the occupant's deceleration profile which you can already customize by changing how the car deforms. To really make a difference vs a high end car we could mandate 3 point seat-belts and helmets like you have in racing world.

Still a 70MPH a head on collision is already fairly safe assuming people are belted the real killers are unbelted passengers, collision debris, and rolling. Edit: Head on collisions still kill a lot of people but they tend to be higher speeds accidents and often involve unbelted individuals. Also we are slightly below 1 death per 2 million hours in a car we just spend a lot of time in our cars.

PS: Worldwide it was estimated that 1.2 million people were killed and 50 million more were injured in motor vehicle collisions in 2004. http://en.wikipedia.org/wiki/Epidemiology_of_motor_vehicle_c...

Nearly every form of motorsport racing requires the following:

5, 6 or 7 mounting point harnesses Head and Neck restraints Helmets

They do this; for front (especially) and rear impact, you have the entire crumple zone, with lots of cross-hatched struts and other components to take away energy in deformation.

There are various side impact technologies to try to 1) prevent ultimate penetration and 2) absorb energy. The problem is the doors need to be relatively thin, relatively light, and contain a bunch of other components, as well as function as doors. Multiple layers is one.

The best right now seems to be use the door to prevent penetration, and use a side curtain airbag to reduce peak acceleration on passenger (along with seat design and seat belts).

I personally picked used cars no earlier than ABS and side curtain airbags whenever friends asked for cheap used car options.

Yes, you're right.. that's why it's more than just the skin of the car.. it's called the crumple zone:

http://auto.howstuffworks.com/car-driving-safety/safety-regu...

The idea is that the entire front of the car is a crumple zone (to absorb the impact), and there's a rigid frame around the passenger compartment.

In a frontal collision, the engine is directed down underneath the drive and passenger. That design alone gives you a few extra feet.

You have often thought of this, but never did any research into what they currently do?

What they currently do is crumple zones. That's not what I was talking about (the entire skin of the car being a honeycomb sandwich).

Honeycombs are a difficult structure to manufacture. They often get mentioned in relation to 3d printing as one of the useful application. They're actually a very strong structure for the amount of material used and were even hand pieced together from wood for some aircraft during world war 2 rather than using more easily manufactured materials due to this advantage.

Indeed. You can drive some older cars right into a brick wall at 50mph and only need to replace the bumper. But that's less good for the occupants who would be killed during a crash like that. Modern car design sacrifices the vehicle for the sake of protecting the occupants.

Modern car design saves lives. Cars in the 1950's had stiff, thick plates and it didn't do them much good. Have a look at the excellent 2009 vs 1959 car crash test video: https://www.youtube.com/watch?v=fPF4fBGNK0U

Car crashes are often called "accidents" in America too. I found it interesting and insightful when my driving instructor back in highschool spent a good 10 minutes ranting about there not being any such thing as a car 'accident' (students mentioning the word "accident" later in the course were scolded, to drive home the point). Obviously you can dream up scenarios that you might be able to really call an accident, but the point was that even when legal blame or liability cannot be found, nearly all car crashes could have been prevented by both drivers driving more defensively and being more alert.

Edit

""You can do things to reduce your risk of accidents" is a vital message, using words in an atypical way can be a pedagogical tool to drive it home"

That was the instructors intent. He wasn't trying to propose a new way for insurance companies or the courts to look at liability, but rather trying to combat thought terminating cliches like "shit happens" (by arguably introducing his own).

This is silly. Nearly all accidents car or not can be avoided by being more defensive and alert. I dropped a glass - if I'd taken more care in handling it and been more aware of my surroundings, I probably wouldn't have. I said something dumb and accidentally hurt your feelings? Jeeze, if I'd only taken more care, been more aware of what I was saying. I accidentally deleted that file? Shoot, should have been more careful and considered better what folder I was in.

"You can do things to reduce your risk of accidents" is a vital message, using words in an atypical way can be a pedagogical tool to drive it home, but insisting that there's some deep sense in which that's genuinely the case is silly.

In firearms circles there's a saying "There is no such thing as a firearms accident. There are only negligent acts."

SOMEONE is always responsible, and should be held accountable.

Similarly "the gun is always loaded".

On it's face, it is a silly thing to say because obviously a gun can be unloaded. The point however is to drive home a respectful attitude towards guns, for the sake of safety.

http://www.youtube.com/watch?v=joMK1WZjP7g

Frontal offset crash test between a 1959 Chevrolet Bel Air vs 2009 Chevrolet Malibu. I know which car I would rather ride in.

Modern lightweight cars are significantly safer than old, heavy cars. Thick steel is good for protecting you from explosions, not collisions.

Equivalent car classes are much heavier now than they were 20+ years ago. It's because of the weight of airbags and safety features.

Car class distribution has changed in the past 20+ years.

Airbags and ABS and crumple zones don't weigh much. The cars are just bigger.

Are you sure about that? I read about people stripping all the airbags out of new Civics and getting dramatically better gas mileage.

What? Seriously? Why don't they strip out the seat belts and headrests while they are at it. In fact, they should strip everything out, so the car is rally-style: nothing but seats, steering wheel and gear stick inside. They would get absolutely AWESOME milage then. Fuck the safety then, eh?

An airbag weighs 10 lbs max, usually 5-8 lbs. Anybody who removes this for "performance" or "fuel savings" is a blithering idiot who should not be allowed near a motor vehicle.

I'm not sure I buy your 10# claim, but even if that's accurate there are six of them in a modern sedan and that's not a trivial amount of weight for a car.

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