Cool stuff! The whole compressed gas energy storage concept is beautiful in many aspects. As presented above, using it for regenerative braking has many potential advantages over the primitive "turn the energy of stopping into heat and dump it" technology, with its many wear parts; and electric regeneration, which has to be dialed down into a low conversion rate to be smoothly controlled. As was pointed out, air systems are light (empty tank) and they are also naturally cushioned.
The air powered commuter car concept packages the air system into a stand alone, solar fueled vehicle. Tremendous weight savings can be achieved when the fuel is compressed air stored in a carbon fiber tank and the propulsion occurs through low tech and lightweight air motors at the wheels. Refueling is simply recharging the tank with compressed air, which can be produced by solar photo voltaic systems during the day and stored indefinitely (the chief drawback to PV energy production is storage, and batteries are problematic because of conversion and transmission losses, toxic components and weight). I don't have a verifiable number at hand, but something like 90% of the energy in gasoline is used up in conversion efficiency losses and in moving the dead weight of the vehicle (3500#), just to transport an average of 200 pounds of human and cargo (passenger car example). Conservation of vehicle weight and improvement of the energy conversion equation, combined with renewable solar energy sourcing... wow!
I agree that we have problems in developing new ways of thinking that are illogical. Resistance to new ideas is almost always a barrier and humanity seeks to maintain the status quo to the bitter end. I'm still not clear on the original motivation for this topic but it appears to be that the poster thinks that trucks shouldn't run more economically because it's just a conspiracy between the EPA and Big Trucking to put the little guys out of business (though that was never plainly stated, to my knowledge). That may be an effect of the rules, and I agree that those effects should be considered and mitigated somehow. But that can't be done if the details aren't daylighted and a rational plan made to influence the rule (besides regressive and hostile opposition).
Trucks should be more economical.
Small businesses should not be wiped out.
The discussion should investigate how to optimize those two conditions, in my opinion. They are not mutually exclusive.
