Detroit's comeback cars

The Volt will be an electric car, able to go 40 miles on a few hours of charging. That will cover most drivers' daily commutes. If you need to go farther, a small on-board gasoline engine will fire up and produce more electricity as you drive.

Where it can pay off is publicity. The Volt has already generated plenty of positive buzz for GM. If it's successful, this car could finally help The General cast off the "tired corporate has-been" image it's been carrying around for years.

That's why GM has actually increased spending on the Volt's final stages of development, even as it cuts back on other cars. The last thing GM wants to be seen doing right now is cutting back on green technology.

NEXT: Chrysler electric vehicles