There are not, really—you're looking at a 3% loss on performance side—but clearly the LNG product is for longer distance. You get six times the value CNG gets, and that's why, in the heavy-duty trucks, LNG is used. There's one company that is doing some research on LNG for passenger vehicles, and that's Jaguar.
Typically what we've seen in the U.S. is that the triangles of LNG corridors are operating very well, particularly in Colorado, Texas, and so forth. The high altitude is not a problem.
The other thing that I see happening is the innovation out of Westport. Their joint venture of Cummins Westport has done a lot of research on the efficiency rate of LNG vehicles.