High oil prices, increased domestic natural-gas production, and a well-publicized push from a former oil man have all boosted interest in natural-gas vehicles in the United States lately. This spring, the natural-gas equivalent of a gallon of gasoline was selling for about $1.50 less than gasoline on average nationwide. And in some places like Utah, where vertical integration of natural-gas utilities keeps prices unusually low, the difference is even larger. Energy independence enthusiasts in and out of Congress are (naturally) gassed about the possibilities. Right now, the U.S. only imports some 2 percent of its natural-gas supply and new drilling techniques that extract natural gas from shale deposits have analysts predicting a sustained boom in domestic production for years to come. However, a dearth of natural-gas pumps at gas stations is a major hurdle to increased use of the cleaner cars; less than 1 percent of U.S. gas stations carry natural-gas pumps for vehicles. Another infrastructure problem is the lack of commercially available natural-gas vehicles. Honda’s Civic GX is the only model currently available, though GM has said it might also get into the biz.