This is an article from last year that descries the CNG situation in Utah, one of the nation's most CNG-friendly states (link):
Troy Anderson was at the gas pump and couldn't have been happier, filling up at a rate of $5 per tank. Anderson was paying 63.8 cents per gallon equivalent for compressed natural gas, making Utah a hot market for vehicles that run on the fuel.
It's the country's cheapest rate for compressed gas, according to the Natural Gas Vehicle Coalition, and far less than the $3.56 national average price for a gallon of gasoline.
"I'm totally celebrating," crowed Anderson, a 44-year-old social worker, who picked up a used Honda Civic GX two months ago. "This is the greatest thing. I can't believe more people aren't talking about it. This is practically free."
Personal ownership of natural gas-fueled vehicles in Utah soared from practically nothing a few years ago to an estimated 5,000 vehicles today, overwhelming a growing refueling network, where compressors sometimes can't maintain enough pressure to fill tanks completely for every customer.
Utah has 91 stations, including 20 open to the public, mostly in the Salt Lake City area. The others are reserved for commercial drivers, such as school districts, bus fleets and big businesses such as a Coca-Cola distributor.
It's possible to drive the interstates between Rock Springs, Wyo., and St. George, Utah -- a distance of 477 miles -- and find 22 places to pull off and fill up.
California has more stations but prices are much higher there, the equivalent of $2.50 a gallon for gasoline.
"Utah has the cheapest prices by a big margin," said Richard Kolodziej, president of the Natural Gas Vehicle Coalition, whose members include utilities, Honda Motor Co., environmental groups and transit agencies.
Earlier this year, Oklahoma legislation introduced a bill for CNG vehicles and refueling stations, and currently, the US Congress is debating legislation to extend and double tax credits for CNG vehicles.