Dune buggies can easily take high speed roll overs with no problem or damage to the roll cage. If you used the same material to make a roll cage for a large luxury car, it would never hold up. It could not even take the weight, much less impact.
The Smartcar is an example of how the smaller a vehicle gets, the greater the strenght to weight ratio. Another was the old aircooled VW, which had amazing strength to weight ratio advantages, and is why it is still the basis for most dune buggies. When you examine larger vehicles, like Cadillacs or limosines, you find that they are weaker in all aspects, because of all the extra weight. It is not possible to scale up the strength to keep up with the weight increases caused by the strengthening attempt itself.
Just examine actual accident damage. You will find with heavier vehicles, there is often total penetration of passenger compartments, with things like side intrusion, etc. While with lighter vehicles, the main structure tends to stay more intact, and the danger to the passengers is more from whiplash as the vehicle tends to bounce off of impacts.
Or you can just study the animal kingdom to see the physics. You won't see animals larger than the elephant on land, because they simply exceed the practical strength to weight ratio. While anyone who has tried to crush a flea knows how difficult that can be.
I agree that mpg is on everyone's mind when gas prices go up, but not ahead of time when it could make a difference. We have had over 3 major gasoline shortages and price spikes in the last 40 years, and each time US auto makers were totally unprepared, nearly failed, and required expensive taxpayer bailouts.
The rest of the world has also already tried the free market, and it has always failed when it comes to vehicle mileage. Everyone only wants everyone else to use less gasoline, so that it will be cheaper for their beheamoth. So I see no way around regulations at the means.
If vehicle buyers had any sense at all, they would not be buying silly, heavy, fragile, and expensive things like power seats, power windows, power locks, remote start, keyless entry, etc. Although car makers have to take part of the blame for not being honest about how these things harm reliability and mileage.
Yes, I agree. Things like more gears, higher reving, variable supercharging, and direct injection to eliminate pre-ignition, would allow a smaller and lighter engine to still have sufficient hp potential, without all the extra weight of a larger engine. Deactivation does not make the wasted weight of the deactivated cylinders to go away.
I agree that added complexity is not the answer. That is why I am skeptical of hybreds. They more than double the possibibility of major component failure, and double the weight of the propulsion systems.
But some some ideas, such as regenerative braking, are simple and could easily reduce fuel comsumption by half. If brakes enaged an air compressor or flywheel, that energy could be used over and over again instead of being wasted, and it is not a very complex system.
And I agree about the hazards of aluminum wire. It was tried in homes in the 1950's, with terrible results. If one wants to reduce weight from wires, the easier solution is just to increase voltage from 12 to 24 or 48, because then wires can be extremely thin, and still carry the same wattage safely.
Head on collisions with anything are pretty final. Hit from behind and run into the guard rail are the threats I've experience from trucks. I suppose a good crush zone helps protect you from the first and a .44 mag handles the second. I still prefer something in the 8000 pound range for general use.
Respectfully, cages are not that different between vehicles. You only protect the passenger compartment. In fact, "dune buggies" or "sand rails" have a bit more expensive cage since the cage is also their main structure (chassis).
I agree with you that for this discussion the focus should be on collisions between passenger cars, including light trucks. Collisions with large trucks have been and always will be catastrophic at medium to high speeds.
Trucks are irrelvant because nothing is going to survive a head on with a truck. Your only hope with a truck is to avoid a head on, and the smaller your vehicle, the easier to manuver and avoid the truck.
Safety cages are easier on lighter vehicles. Dune buggies are easy to make a safety cage for because they are light. If you had to make a safety cage for a big truck or even a Cadillac, it would be essentially impossible. The heavier the object is, the worse the strength to weight ratio. There is no way around the laws of physiscs. That is why an ant can lift 100 times its own weight, and we can't. We are too big. Small cars are inherently stronger.
The only problem is when 2 vehicles collide head on, then whomever has the greatest mass, will destroy the other vehicle. And the solution to that is not have head on collisions, or try to make all vehicles smaller.
I have survived several motorcycle accidents. Apparently, I was "allowed" more than 1 accident. However, I get the point: cars (for most people/situations) are safer.
And, yes, more mass will increase your chances of survival in a crash.. but not because of a stronger cage around you. It has to do do with rate of change in velocity (think bug vs windshield for mass differences), crush zone size (de-accel time/distance) and occupant containment (seat belts). Race cars drivers have survived crashes in cars weighing less than 2,000 lbs - hitting brick walls (straight on) while traveling in excess of 150 mph. Numerous times. It had little to do with the additional mass of their "cage" (or even use exotic materials).
Regardless of this, it is not likely the payloads on 18 wheelers will be reduced to reduce risk to other motorists - there will never be the "political will" to do this. 100,000 lbs against 1,000 lbs or 3,000 lbs - the odds have not changed much with additional 2,000 lbs - the smaller vehicle is going to lose, big time. The only change: chances of hitting a car of equal or smaller mass. And if all cars are lighter, the odds have not changed. The reality is likely to be something between the two extreme examples - a slight increase in risks compared to the avg car on the today.
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