Distantly related to the subject is the use of unleaded fuel (they are trying to make it the standard for lighties as well as cars). When they took out the lead and mandated catalytic converters they supposedly cleaned up the emmissions, but if they were right, the tailpipes of all those cars (and light airplanes if they have their way) will produce, instead of NOX, NO, CO and HCO (with a little bit of lead oxide), mainly CO2 and Water Vapour. Those two items are supposedly what is causing global warming. Maybe the problem of smog is being shoved over and not solved at all.
It takes about 10% more crude to produce a gallon of gasoline, and the new gas, without the lead, does not produce the same energy so that cars go about 10% less miles on the same volume of gas. And the Cat wastes another 10%, which adds up to a loss of around 30% in crude for the same miles driven.
Much more sensible to use the old fuel and to make the motors smaller or more fuel efficient, thus reducing the emissions. The less fuel burnt, the less cr@p in the air.
Instead of lead, which was never as serious a problem as the "experts" tried to make it out to be, we now have Benzene, which is a real poison. After fuelling the old Cessna 172 and checking the oil, it is safe to wash your hands with the fuel from the strainer, but if they take out lead and put in benzene, watch out! And if you value your kidneys, don't breath the vapours when you are filling your car. Savage stuff.
Imagine how we would have loved to have all the goodies that are now standard, such as fuel injection, computer controlled ignition and mixture control, lean burning combustion chambers etc, in the days when we were modifying our own cars. A modern engine, using the old fuel, would have great mileage, and with it, reduced emissions. And not so much CO2/H2O, thus not as much global warming at the same time!