New cars use medium- and high- strength low alloy steels that are
much stronger than the mild steel used in older cars. There are also
differences in frame construction--i.e. the unibody.
I don't have data on thicknesses, but the trend has been thinner
in recent years.
In addition to thicker sheet metal, its been claimed that most early 50's
era cars would crash test better than new cars, at least as far as the
driver's compartment goes, because there is more metal enclosing the
drivers compartment in the older cars compared to the "greenhouse of glass"
on the newer cars.
It also seems that you often hear that cars are breaking in two halfs in a
bad crash with today's cars. I don't remember that happening very often back
in the old days. So have all these safety laws really done much for us,
other than seat belts and air bags?
So where has the huge improvement in driver survivabilty come from ? I
don't want my car to be in fine shape, while I am smashed to pieces
inside a 1950s car....Modern vehicles have very carefully designed crush
and crumplezones which exclude the passenger compartments.
My parents' 1987 Nissan Stanza wagon was broadsided by a Ford F-350
farm truck about 15 years ago.
The drivers side door was driven 2 feet into the car.
My brother was driving and suffered a punctured lung.
My dad was in the pasenger seat and suffered bruising.
My Mom was in the back and slammed from the passenger side to the
drivers. side permanently damaging her shoulder.
I wennt to the wrecking yard to see what we could pull out of their
The car looked like a stepped on coke can, and yet all the doors not
directly impacted opened just fine.
The owner of the wrecking yard said that he had been wrecking cars for
40 years and 40 years ago he would get in a Packard with a dent in the
fender where nobody survived inside the car.
Now, he said, I pull in crushed pop cans where everybody gets out alive.
Progress?, well maybe if you want to live in an accident, but it sure
cuts into the profits from selling used car parts.
I saw an exhibit in the Deutsche museum in Munich maybe 15 years ago, it
was a 1950s Mercedes IIRC tested at the time. They crash tested it at
speed and the damage crushed the car by maybe 2" which was good for the
car, it went on to say that they realised that the decelleration would
have killed the occupants. After that more thought was put into the
design of crush structures to absorb the energy and save the occupants
not the car.
Ernie Leimkuhler wrote:
Seat belts primarily prevent occupant ejection in a crash, and that's
usually a good thing, but they do little to reduce the forces on the
occupant's body in a crash. Air bags buffer the impact between the
occupant and the interior of the car in a frontal crash, also usually
a good thing, except when their deployment in a multiple impact
crash, or a false trigger deployment, causes the driver to lose control.
But the big improvements in survivability in crashes is due to the
*controlled* crush and crumple zones designed into modern cars.
This dramatically reduces the G forces endured by the occupants.
In other words, the sudden stop isn't quite so sudden when the
car is able to crumple. As has been said many times with regard
to falls, it isn't the fall that kills you, it is the sudden stop at the
Same thing in a collision, the longer you can prolong deceleration,
the lower the peak force the occupant's body has to endure. The
time involved to make a dramatic difference isn't all that much either.
For example, if a crumple zone can prolong deceleration from 1
millisecond to 10 milliseconds, the force on the occupant decreases
10 times, if 100 milliseconds 100 times, etc.
Most modern cars have crumple zones that reduce impact forces
on the occupant by 5 to 10 times compared to cars from the 1950s.
The best ones reduce the forces by nearly 100 times.
Also, most modern FWD cars are designed so that the engine
and transmission break away and submarine below the passenger
compartment in a frontal collision. This prevents the motor from
intruding into the passenger compartment, as was often the case
with older designs. Some front engine RWD cars are designed to
do the same (they use carbon fiber drive shafts designed to shatter
in an impact and allow the engine and transmission to move down
and to the rear without becoming a pogo stick). Of course steering
columns are collapsible, so they don't spear the driver in a crash.
The passenger compartments themselves have been reinforced
so that they don't collapse in on the occupant in a crash or rollover.
There are side door beams, stronger A pillars, etc. They certainly
aren't as good as a NASCAR cage, but they are remarkably more
effective than just the heavier sheetmetal in older cars. The interiors
of cars have had hard and sharp things removed too, so if the
occupant does strike a part of the interior, less damage will be
The fatality rate per 100,000 miles driven dropped *dramatically*
between 1950 and 2000, with most of the drop occurring in the
last decade. That's primarily due to the use of CAD to purpose
design in optimized crush zones, and to strengthen the passenger
compartment *in the right places* to minimize intrusions into that
space in a crash.
It is worth noting that my Nissan 350Z, one of the best rated cars
for crash survivability, actually weighs more than a 57 Chevy. So
does the 2005 Corvette. Think about that, today's small 2 seater
sports cars weigh more than a full size 50s sedan. Much more of
that weight is in the *right places* to reduce impact forces on a
driver in a collision, and to prevent intrusions into the passenger
This weight thing surprised me a bit. The 350Z weighs 3450 pounds,
the new Corvette weighs 3224 pounds, a 57 Chevy Belaire (283 with
Powerglide) weighed 3175 pounds. Now considering that the modern
cars make extensive use of aluminum, plastics, and thinner sheetmetal,
that extra weight has been put into the structure *where it counts*
for crash survivability. Cars are no longer just sheetmetal boxes sitting
on a pair of C channel rails.
The bumpers on 55 and 57 Fords were made from tough and thick steel.
I remember being rear ended in my T-Bird and had all 4 quarters bent, both
The 55 Ford in front of us didn't get a scratch on the bumper. The heavy frame
strong bumper just crumpled the front end. The Bird never flew with me again.
The drunk went to jail.
Martin Eastburn, Barbara Eastburn
@ home at Lion's Lair with our computer email@example.com
I don't know what gauge is used, but I believe it varies with the
manufacturer. I recently took our PT Cruiser to Dent Masters for an
estimate ($1,700) and he said if it was a Honda the damage would have been
much worse. The sheetmetal of new cars is very flexible, just press with
your thumb (carefully!). Like others have said, the new designs are made to
same the occupants, not the car itself. My Challenger has real steel, hee
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