It's a bumpy ride on the Hydrogen Highway

Cadillac unveiled a concept car this week that runs partially on hydrogen, adding to the ranks of futuristic vehicles powered by the universe's most common element. Yet even if you could drive it -- there's only one now -- you couldn't get from L.A. to San Francisco, because there aren't enough fueling stations. The state, through its Hydrogen Highway program, has been pushing to create a network of 100 hydrogen fueling stations by 2010. But the closure of two stations in recent weeks, and the pending closure of a third next month, will drop the number to 22.