The WSJ has an interesting article on long-haul natural gas trucks. The costs appear prohibitive at the moment: "United Parcel Service Inc., which runs one of the country's biggest truck fleets, pays about $95,000 for an average long-haul "tractor"—the front part of the 18-wheeler, housing the engine and driver. It recently ordered 48 natural-gas versions at a cost of $195,000 apiece—about double the cost of a diesel model, said Mike Britt, UPS's director of engineering and maintenance." Still, very interesting.