The vehicle is the first of its kind to be used in a public fleet in the United States. It is one of the cleanest forms of public transit, producing practically zero harmful gas emissions and other pollutants.

"We're setting the standard for cleaner air here in the Coachella Valley," said SunLine general manager C. Mikel Oglesby at the agency's headquarters in Thousand Palms.

Distinguished guests board the United States' first hybrid bus in Thousand Palms. The hydrogen fuel for the bus is created from wind power and solar power.

The bus cost about $600,000 to build and is part of a million-dollar U.S.-Canadian initiative aimed at bringing cleaner-fuel technologies to public roadways. SunLine is one of the first public transit agencies in the nation to convert its entire fleet from traditional diesel to alternative fuels.

The 40-foot-long bus goes into daily service immediately on one of the busiest lines in the desert. The bus stops near the College of the Desert, the Westfield Shoppingtown in Palm Desert and The River entertainment complex in Rancho Mirage.

As with hybrid vehicles sold to consumers, the bus is powered by an internal-combustion engine and an electric motor. However, instead of burning gasoline, it burns hydrogen.

To further boost its efficiency, the bus also recovers some of its energy from regenerative braking, which captures kinetic energy otherwise lost as heat in the brakes.

The fuel, generated at SunLine's headquarters, is created using wind power and solar power. The hybrid bus will refuel at the Thousand Palms facility. Hydrogen tanks are stored in the vehicle's roof.

The bus does not use fuel cells, which utilize hydrogen mixed with oxygen to produce the electricity that propels a vehicle.

Ken Koyama, a project manager at the California Energy Commission, said the bus provides a link to the "hydrogen highway," a term coined by Gov. Schwarzenegger that represents his plan to increase cleaner-fuel vehicles in the state.

"They have a terrific infrastructure here," Koyama said. "If fuel-cell vehicles are the future, this bus will provide that transition."

The bus is also passenger-friendly, said Frank Shardy, a SunLine maintenance supervisor who is training bus drivers to operate the vehicle. It is low enough to the floor that passengers do not need to climb up steps to get inside.

The engine is strong, and the ride is smooth and quiet, he said.

"When you step on the pedal, you have instant power," Shardy said. "It's much like a golf cart, but on a much larger scale."

The extra power will also improve the bus's transition into traffic from a bus stop, said Tommy Edwards, maintenance director.

If SunLine chose to mass-produce the hybrid bus, the price would come down to about $350,000, Oglesby said. That is the average cost of one of the agency's natural-gas vehicles.

A single hybrid bus that uses gasoline instead of hydrogen would cost about $450,000 to build, he said.

In 1994, SunLine's board of directors voted to switch its entire fleet to cleaner-fuel technologies. More than 100 vehicles in service today use some form of natural gas.

SunLine provides bus service to nine desert cities and unincorporated parts of Riverside County.

The agency also operates a hydrogen generation and education facility to demonstrate tactics for cleaner-fuel production.

SunLine officials hope the "H2" bus will be easily recognizable since the exterior is wrapped in illustrations of blue skies and white clouds. It will be in service until Jan. 10, when the vehicle will be sent to the Canadian province of Manitoba for cold-weather testing.

If all goes well, the bus will return to the desert in the spring.