Consumer pressure works, it has been proven throughout history, if there is a large enough demand for a product someone will fill that demand. so why not use it ? if enough people tell the big 3 ( ford GM and Chrysler) that we want CNG cars they will produce them because it helps thier bottom line.not to mention the fact that once thier current engines have been set up to run CNG ( and they will undoubtedly use current engines because it involves less retooling) conversions for recent model used cars will become a simple factory available direct bolt on conversion that can be done at Sams auto repair with ease. not long after the availablility of OEM CNG parts you will begin to find them available at Autozone and Checker from aftermarket suppliers. yes I know this is pretty simplistic but the fact is that with a little work it would happen. no legislation needed because the will of the consumer is a very powerful thing. the average professional mechanic could easily learn how CNG fuel delivery works and that would be the primary difference. you would soon see your local " Joes Gas N Go " putting in CNG pumps.
the power of the consumer in a free market economy is virtually unlimited , lets use it.