Compressed natural gas may not be given the publicity it deserves. After all, it burns cleaner than other fossil fuels, it can be collected from landfills and waste facilities and it's abundant in North America. Regardless, CNG doesn't seem to get much support from the government as an alternative to gasoline or diesel; certainly much less so than hybrids or fully electric vehicles. This lack of government help for the fuel makes it much less attractive to consumers than other alternatives.
Mercedes-Benz is still interested in testing the American CNG waters, though, and the German automaker is proving it's serious by bringing a natural gas-powered version of its B-Class compact MPV - the BiFuel B170 NGT -to the Auto Show that's currently taking place in Washington D.C. A CNG-powered B-Class is already available in Europe (and South America), where natural gas, sometimes referred to as autogas, is a more popular choice than it is in the United States.
[Source: Automotive News - Sub. Req.]