I don’t know much about this so I am posting here. It appears that car bodies are made out of materials now that break apart rather than compress. Did the older cars still have quarter panels or was the body made of fewer sections? Has this proven to be safer? I would hope so.
All you said is true and they are safer. There are lots of ways to build a car.
It’s actually the opposite.
Old cars, pre-1970, were commonly made by putting body panels on a steel frame, the same way most trucks are now. Car’s now are designed wherein the body is actually the frame and absorbs the stresses from the engine and operation. It’s commonly referred to as “uni-body”. The engine and drivetrain are on a “subframe” that’s mounted to the “uni-body”.
The engine/drivetrain assembly is made to go under the unibody to absorb energy without transmitting it to the passenger cabin, and fronts and rears of the car are designed to crumple in a controlled manner as “crush zones”, again to absorb energy.
It has allegedly proven to be safer, and the theory is “sound”, however separating out how many casulties are prevented from that vs. the use of seat belts vs. headrests vs. other new safety technologies that all came into being during the same era would be pretty tough.
It’s not the fall that killed him but the sudden deceleration at the end of it 
You’re right about the empirical data from the “field”. One thing they can do is accurately measure deceleration forces on body simulators. I’d bet they have miles and miles of files…containing survivability estimates for every conceivable combination of restraints, impact angles, degrees of impact, ad infinitum. Obviously, the crumple zones won’t be nearly as effective if the passenger isn’t restrained. It’s the combined effect that improves the odds of surviving.
Actually, car bodies (at least the important, structural parts of them) do compress, and at a controlled rate in order to absorb the force of the impact. Years ago, car bodies also compressed upon impact, but not at a controlled rate and not as much as the car bodies of today. As a result, the passenger wound up absorbing much more of the impact in the collisions of yesteryear, rather than having the car’s structure absorb it.
As an example, imagine that you are in a head-on collision while driving…let’s say…a '53 Buick and it collides with…let’s say…a 2008 Honda Civic. After the impact, the Civic will appear to be virtually destroyed, while the '53 Buick will have relatively little body damage. However, the driver of that Civic will walk away with few injuries (if he was belted in), while you might be severely injured and very possibly killed by colliding full-speed with the interior parts of your tank-like car.
Cars today are designed to protect the passengers, and as a result, the car itself might not survive the accident from which the passengers can walk away. But, I think that most of us will agree that this is the way that it should be.
As to the body parts that “break apart”, you are probably referring to the plastic and fiberglass body parts that are not structural. Using plastic and/or fiberglass for non-structural parts saves weight, which saves gas every time that you drive the car. If these parts break, it might not look pretty, but this has no effect on a vehicle’s crash-worthiness.
The most dramatic example of this are Formula 1 racing cars which routinely crash at 100 mph or more and spectacularly come apart, When the car comes to rest, the driver often walks away. All those pieces flying off were absorbing the impact! The “cage” which holds the driver must stay intact.
Another dramatic, but tragic crash was Pricess Diana, whose Mercedes S Class ran into a Paris, France tunnel abutment at 100 mph. Three passengers who were not wearing seat belts, incluidng Diana, were killed. The body guard, who was sober and wearing his seat belt, survived with some injuries. This type of crash in heavy old style US car likea Buick Roadmaster, would certainly have killed everyone.
Theoretically, all that modern technology is very nice. But in practice, these “crumple zones” are only useful during a major collision that would otherwise have been fatal or nearly fatal. The problem is that a modern car with crumple zones will sustain way too much damage in a minor collision compared to the old full-frame cars. Junk yards are full of late model cars that have been written off as a total loss after accidents that couldn’t possibly have been life threatening. Having been involved in accidents in both types of vehicles over the years, I personally am ambivalent about this issue. To use the above analogy, while I’d prefer to be safe in a 2008 Honda during a major accident, in the average fender bender, I’d much rather take my chances in a '53 Buick.
“To use the above analogy, while I’d prefer to be safe in a 2008 Honda during a major accident, in the average fender bender, I’d much rather take my chances in a '53 Buick.”
Unfortunately, accidents that are caused by other drivers don’t give us the option of deciding whether we will be in a major accident or a fender bender, nor do they allow us to select the type of vehicle for a particular type of accident. While I have driven without any kind of accident since 1971 (for a total of over 450,000 accident-free miles), I value my life and I will gladly shoulder whatever out-of-pocket expenses I might need to pay over and above what is covered by car insurance to pay for the fender-bender damage to a car that has the ability to protect me in a major accident.
You may feel differently, and that is certainly your prerogative. I just hope that you have insured yourself sufficiently so that your loved-ones are provided for if and when you are involved in a major accident in that '53 Buick.
I’d rather be in the Honda because of the airbags, head restraints, seatbelts, and collapsable steering column.
On a previous post on safety I quoted the fatality statistics since 1955. Person miles travelled went up by 15 times while the total fatalities are still between 40,000 and 50,000 per year for all states. So, cars are 15 times as safe as they were in 1955 (no seat belts, crash padding, telescoping steering wheel, air bags, etc, etc.).
Drivers, on the other hand, are no more competent than they were then; perhaps even less so, since they want the car to drive for them.
The number of fender benders, and light injury accidents went up sharply of course, but not by a factor of 15. What this proves, regardless of what some want to believe, is that today’s cars are safer, although they cost more to fix in accidents. However, the cost of medical care in the US is atronomical by world standards, so writing off the car, but saving the driver, is a good trade-off!
I’d rather be in a Buick Lucerne than a new Honda or an old Buick in an accident. The Lucerne has the advantages of both: big, unibody, and all those bag thingies.
And Ferrarri Enzos. If there are any left that haven’t been totalled already.