Not trying to start a war, but if you don't think the tanks being large are an issue, go look at city truck that's CNG powered. The entire bed is taken up with tanks. That's a big drawback.....at least for me. I agree with all the good points though and the US should be doing more so that vehicles can run off CNG. Surely there has to be a way to compress it perhape even further and make the storage tanks smaller. I don't think that it's really been studies as much as it needs to be because the big oil companies don't want it to be.....and that's really stupid considering that CNG is a product that they sell.