Now that the market for greener American cars finally is arriving, it looks a little different from what was expected.
Some green-vehicle technologies that looked like sure bets for the second half of this decade are lagging. And some technologies that seemed like long shots seven model years ago have become viable.
Coming up on the outside in this horse race for higher fuel economy: diesel engines, aluminum bodies and — still a long shot — hydrogen fuel cell-powered vehicles.
Struggling to live up to expectations: electric vehicles and plug-in hybrids.
And the big-selling fuel-reducing technology of the moment has turned out to be a more efficient gasoline engine.