<snip>
> Re 70 mph crashes: even 35 mph frontal crash tests put occupants near
> the limits of survivability in both large and small cars. In side
> impacts (at 31 mph), G forces at the hip can be 100 or more. Although a
> Smart Car (and many other cars) can appear (in web videos) to survive a
> 70 mph barrier crash with the safety cage still more or less intact, no
> occupant can survive such a crash, and none of the car's systems are
> designed for such impacts. (Truth be told, cars are designed to the
> crash tests, just as they are designed to the EPA tests. There are some
> small exceptions, with Volvo, for example, having gone beyond the
> requirements, especially in the early days, but in cases where the
> standards are lax, as in rollover protection, the manufacturers are lax
> too.)
<snip>
I do share some of your sentiment that the current auto safety standards
haven't progressed as fast as other parts of the auto world. Especially
domestic auto manufactures who have followed more than lead for 3
decades. (followed regulations, followed insurance institute, followed
eurapean, etc)
But we should add to the above statement. While the G forces you mention
are obtainable, they are only there for fractions of a second. A crumple
zone allows us to spread out the G forces over time and reduce the peak
absolute value. The irony of some of those tests is they are vehicle
against immutable object. Normally we hit something that also deforms.
Some of the tests are that way on purpose to isolate testing interactions.
It is the dissipation of energy that matters. That is why the race car
that swerves into the wall and just stops unspectaculary kills the
driver and the race car that flips rolls and slides taking all that time
to dissipate the energy, spares the driver.
Something I would like to see, and I have seen this used in amature road
racing, is a dual seatbelt system. (this is in my ultimate EV car
design) a center roof mounted pod contains a second retractor and the
seatbelt crosses the chest the other way and clips at the left hip
(driver). I have not devised a slick way of doing this yet. This would
help keep a person's torso straight in a wreck and help prevent sliding
out from under the belt in side impacts.
I got in a wreck in 1990 in which a cop was chasing someone at high
speed. The intersection was blind and the light was green and as I went
through the intersection the guy in the monti-carlo ran the red light at
80+ and hit the front left corner of my mitsu pu. It was kind of a equal
angle impact which pushed the monti-carlo a lane over and pretty much
stopped me in about 5 feet. The cop had to slam on his brakes and almost
broadsided me. My body moved forward and hit the belt, but because of
single angle across the chest, my upper body pivoted on the belt
damaging my back and my chin hit my left bicep and I watched my glasses
fly out the window and into the street. If there were a pair of belts,
this would be minimized.
I have 4" 5 point belts in there now, cause I was racing it. I use to
drive daily with those (4 point) cause the others didn't work well with
the race seat and I can say they are inconvenient enough that people
wouldn't used them and they have a degree of unsafety as you can't look
over your shoulder as easily. So I think dual retractors and a criss
cross is a good compromise (and works well for the "better half" of the
market too)
I also know the degree of belt stretch is important and the load area. I
think the simplest and best first safety set would be to have the car
manufactures be required to bump up the belt weave thickness and widen
the belts a 1/2" to an inch.
And for those who would bring up air-bags at this point of the
conversation, They do not inflate the way hollywood depics it, they
deflate immediately. So if you are on the highway and get in a multi-car
pileup, the first impact where both you and the other guy were just
doing 70 deploys the airbag, but you are still doing 45mph the next
impact when you both plow into the simi rig on it's side, gets you.
An airbag can only deploy once! (pst, how many race cars have airbags,
if they are such a great idea)
_______________________________________________
General EVDL support:
http://evdl.org/help/Usage guidelines:
http://evdl.org/help/index.html#convArchives:
http://evdl.org/archive/Subscription options:
http://lists.sjsu.edu/mailman/listinfo/ev
