20-passenger unit nearly doubles mileage, reduces emissions by 30%

NAPA — Napa Valley Unified School District is set to start using the nation's first and only gas-electric hybrid small school bus.

The Nexbus is scheduled to begin ferrying special needs children this week.

It's another coup for the district, which two years ago had the first full-sized plug-in hybrid diesel-electric school bus in the state.

"The difference between the two, besides size, is that the Nexbus engine turns off when it rolls to a stop, conserving fuel and reducing emissions," said Ralph Knight, the district's director of transportation.

It was tricky to design because school buses must retain steering ability, air brakes and hydraulics after the engine goes off.

Mr. Knight's fleet of Type A (small) buses - which comprise half of the 52-bus fleet - have always been diesel because there were no alternative-energy options in the class, he said. They get nine to 10 miles a gallon and idle frequently as children, some in wheelchairs, enter and exit the bus.

"We just took delivery, but we're already impressed with Nexbus. I drove it down from a show in Reno myself," he said.

The little bus, which can accommodate up to three wheelchair positions and carry a maximum of 20 passengers, is expected to get 16 to 17 miles per gallon in start-and-stop mode and reduce emissions by 30 percent. It's in Sacramento getting checked out and licensed by the Motor Vehicle Department.

Unlike non-hybrid vehicles, engine-off hybrid electrics like the Prius and Nexbus operate most efficiently in start-and-stop mode, not highway driving. So producer Collins Bus Corp. is promoting it heavily to school transportation departments.

Nexbus drew lots of attention at the School Transportation expo in Reno before Mr. Knight carried it away.

The bus employs an Azure (previously Solectria) hybrid drive train on a Ford chassis, currently used for Ford's one-ton trucks and the most popular chassis for Fed-Ex trucks.

"All the bugs have been worked out. Everyone is happy with the Ford chassis, and I have a lot of respect for Azure Dynamics, because Solectria, which is now part of it, sold us an all-electric bus that ran three-and-a-half-years without one down day before it finally wore out," said Mr. Knight.

As for how long Nexbus and other hybrid electric vehicles will run, nobody knows. Most batteries are warranted for 150,000 miles but could well run for twice that, said Mr. Knight.

The Nexbus cost $140,000. It was financed in part by Prop. 1B, which set aside funds to replace aging school bus fleets, and partly by the Napa Air District, which relieved the school district of a remaining $25,000 burden.

"Our air district has been very good to us," said Mr. Knight.

Napa Ford and Zumwalt Ford dealers will receive training in driving and working on the Nexbus, which is expected to be a boon to Ford if it takes off. Cutaway buses in airports and hotel shuttles are among the many possible applications for the vehicle.

Collins Bus Corp. is headquartered in South Hutcheson, Kan. Azure Dynamics is headquartered in Oak Park, Mich.