I'm all for spending less money on fuel and using green fuels, but this whole propane thing reminds me of the gasahol fad on the 70s. Everyone swore gasahol was the new thing and that regular gasoline was a thing of the past, but it never caught on. Like propane, it tended to cause other problems with the cars.
I'm holding out for an electric car that runs at Interstate speeds and charges on household current. I hear progress is being made and research continues. We'll see. In the meantime, I’ll do the best I can to conserve fuel. Gas is too dang expensive to do anything else.