GMC is going green.

This year, the company is introducing a hybrid version of the GMC Yukon, and it promises to be an important product for General Motors.

It gets about 25 percent better fuel economy in combined city-highway driving, and about 40 percent better mileage in city driving. Although figures have not been set by the EPA, GM said the Yukon could get about 20 mpg in the city, about 22 on the highway, and about 21 overall.

While those figures may not seem like much in the days of hybrids that get 50 mpg, they certainly look good compared with other SUVs.

It features the world's first production two-mode full hybrid propulsion system in an SUV, and includes a 6.0-liter V-8 engine that has active fuel-management technology, which means that in certain situations, such as cruising or in city traffic, the engine switches to a four-cylinder mode, thus saving gasoline.

The Yukon can run on electric power only, engine power only (a 6-liter, 332-horsepower V-8) or any combination of engine and electric power. In lightning-quick calculations, the SUV automatically decides what is needed.

The system also has electric power steering instead of the belt-driven system that uses more gas. Other steps intended to lighten the weight of these SUVs include changes to the seat design and lighting fixtures, aluminum hoods and liftgates, lightweight wheels and low rolling-resistance tires.

I've driven the new Yukon hybrid and its peer, the Chevrolet Tahoe, and I can tell you that its a pretty smooth experience in both cases. They are both quiet and comfortable.

As you drive, a gauge helps you obtain the best mileage if you keep the arrow indicator in the noon to 2 p.m. position. If you're curious what the truck's hybrid system is doing, there's an easy to understand graph on the navigation screen that illustrates which parts of the system are working and under what conditions. That's better than the bewildering bar graphs and charts used in other hybrids.

Although General Motors has yet to announce prices for the hybrids, I expect them to be $1,000 to $2,000 more than a conventional model.