2008 GMC Yukon in Richmond

America's environmental chickens have come home to roost. For nearly two decades, we've blithely bounded from sea to shining sea in ever porkier sport-utility vehicles fueled by cheap gasoline. Now, many of us face the prospect of personal bankruptcy, not to mention social ostracization, if we continue to indulge in the privilege of carting home our groceries in three-ton trucks. But old habits are hard to break. Isn't there some way we can have our proverbial cake - lower emissions, less consumption of fossil fuels, Al Gore's approval - and eat it, too, by still driving big SUVs that can haul our families and tow our toys?

Well, Tipper, perhaps there is.

General Motors has spearheaded a new Two-Mode Hybrid system in association with Chrysler, Mercedes-Benz, and BMW. The system has been described in detail in these pages in recent months, and in our February issue, we gave GM our 2008 Technology of the Year award in recognition of its work on the system. (The Two-Mode Hybrid system, or TMH, recently debuted in the Chevrolet Tahoe and the GMC Yukon. It will also appear in GM's full-size trucks this fall and eventually in cars.) But what remained was to put TMH to the test in the real world, by driving two GMC Yukons - a conventional 2008 model with a 5.3-liter V-8 and a 2008 Yukon Hybrid, both with four-wheel drive - back-to-back over several days and hundreds of miles.... Read full article