When they hit showrooms by the end of 2008, the Chevrolet Silverado and the GMC Sierra will mark the return of a full-size hybrid pickup to the auto market. Chevrolet first introduced the full-size hybrid pickup in the 2004 model year and later abandoned the concept.

Returning for 2009, the Silverado and Sierra will sport Vortec 6.0-liter, eight-cylinder gasoline engines and 300-volt electric motors.

The General Motors siblings will use GM's Active Fuel Management system, which allows half of the engine to idle when cruising on the highway for better highway mileage. They are EPA rated at 21 miles per gallon in the city and 22 miles per gallon on the highway.

The pickups will be able to reach speeds of 30 miles per hour on electric power alone, even in some towing situations, greatly improving performance in city driving and stop-and-go conditions. The pickups are rated to tow a maximum of 6,100 pounds.

They are available as either two-wheel-drive or four-wheel-drive vehicles and are available in crew-cab body styles.

General Motors warrants the hybrid components for eight years or 100,000 miles.