In the automotive world, the term "hybrid" didn't even exist 10 years ago. Now, it's practically defined by the success of Toyota's homely Prius. From Leonardo DiCaprio to John Q. Public, driving a hybrid has come to show that you care about the environment--maybe more than other people do. But there's one more thing it says about its buyers: They're perfectly happy compromising on all of their towing and hauling needs (and we can't remember the last time we've seen more than two people in a Prius). Enter GM. As if to squelch the voices of SUV-haters, GM brought out its long-awaited two-mode hybrid system in the full-size Chevy Tahoe (and GMC Yukon; see sidebar) and this could be the game changer.

First seen in huge diesel/electric buses, the system was produced in partnership with BMW and DaimlerChrysler (now The New Chrysler). The Tahoe's version of the system is reported to improve city-driving fuel economy by as much as 40 percent and highway driving up to 25 over a comparably equipped 5.3de and out; and they've carefully integrated all the systems to work together.

When listening to GM Hybrid leaders tell their story, you get the sense every excruciating detail was discussed and deliberated. "This is a strategy we've had in place for quite some time. We've always had the means to make a one-off specialty vehicle, but we wanted a bigger footprint, something that could make a huge impact," says Mary Sipes, vehicle line director, Full-size Truck Group. "That's why we started with the GMT900 platform--we wanted to get big numbers on a big-volume product."

With the GM bigwigs in town with a new Chevy Tahoe Hybrid 2 Mode, the first here on the West Coast, we went for an entirely too short drive around Southern California. To fully test this vehicle's claims, GM engineers and I drove through the jammed side streets of Santa Monica, Los Angeles, and Beverly Hills in the heart of early-morning rush hour.

The Hybrid looks sportier than a regular Tahoe, thanks in large part to the lowered stance and larger, color-matched front bumper and air dam. The front end has been reworked to eliminate drag-causing bumper gaps, tow-hook holes, or rough seams. The key is to move oncoming air around the vehicle as quickly and smoothly as possible. Even the sidesteps are aerodynamically tucked behind the front tires and under the door panels. Beyond that, the only visual giveaways on the outside are a small set of side- and tailgate-mounted "Hybrid 2 Mode" badges. Behind the wheel, the interior dash is almost identical to the conventional full-size SUV, with the exception of a small "economy" gauge on the dash. On the nav screen, an easily accessible animated screen charts power flow and direction.

As we started our cruise, I monitored flow from the battery packs to the driveline to the rear wheels. The only detectable sound came from the rear as a small fan cooled the battery pack under the second-row seats. Electric drive took the SUV to about 20 mph, but there was a slight vibration in the seats as the icon on the information screen showed the 6.0eter indicated the engine had shut off, and the regenerative brakes were channeling power back into the battery packs. The ride itself felt rough, as if the shocks were a tad too stiff. No doubt the low-rolling-resistance tires have something to do with that as well. And it wouldn't surprise us if the tire pressures were up.

Overall, the system drives like that of a Toyota Prius, but seems to lack the style, function, or power trade-offs. The Tahoe looks normal, hauls like a Tahoe should, and when you want to flatfoot it to pass someone, you get all 320 horses from the all-aluminum 6.0uel economy," says Mark Cieslak, assistant chief engineer for Chevy Tahoe Hybrid, from the passenger seat.