Seattle Superbus; A northwest oasis is the main testing ground for hybrid mass transit.(Cover Story)

Byline: Andrew Romano

Jim Boon is a hybrid kind of guy. He drives a Toyota hybrid to work, a Honda hybrid on weekends, and as a manager for Seattle's public transportation system, he recently placed the world's largest order for hybrid electric buses.

Now, with the biggest hybrid bus fleet in the world, Seattle has become the main testing ground for a technology that claims it can drastically cut air pollution and fuel consumption. In the late 1990s, small demo fleets of 35 buses or less started cropping up in cities such as Tempe, Arizona. Sixteen of these early hybrids still service Genoa, Italy, where drivers switch from diesel to electric power when passing the city's downtown architectural treasures. But no city has gone as far as Seattle, which last year bought 235 GM hybrid buses at $645,000 a pop. When the final one hits the streets this December, the region's bus system will be 15 percent hybrid.

But why Seattle, and why now? The Pacific Northwest has long been a hotbed of both crunchy green politics and cutting-edge technology. Fourteen years ago, the Seattle area bought 236 Italian-made Breda buses to service a kilometer-long downtown tunnel. They were supposed to operate as clean and silent electric trolleys underground, but the switching mechanism often failed and "the bus drove through the tunnel as a diesel," says Boon. "It was pretty loud and smoky."

When the Bredas hit mandatory retirement age in 2002, Boon went shopping. He chose the GM model because it uses an automatic transmission and diesel boosts that provide the power needed to scale inclines without strain. In hilly Seattle, the prospect of a hybrid that could climb like a diesel but accelerate without belching black fumes ...