County Bus Fleets at Forefront of Drive for Cleaner-Burning Fuels

Soot-belching buses are getting harder to find in Ventura County as big transit fleets rapidly convert to cleaner-burning fuels, driving down smog and establishing the county as one of the first in the nation to substantially rid itself of dirty diesel engines.

During the 1990s, operators of three of the county’s biggest transit bus fleets have made smokeless buses a priority. The result is cleaner air--air quality officials say replacing a diesel bus with one powered by natural gas is equivalent to removing 35 cars from the road.

Credit the effort to environmental concerns, improved engine designs and an infusion of public and private cash for cleaner, but more costly, coaches.

More than three-quarters of the buses run by South Coast Area Transit, the county’s biggest fleet with 44 vehicles, are powered by low-polluting engines, and more clean coaches are on the way.

The big white buses, which sport turquoise and tangerine trim and the slogan “clean air fuel for a cleaner environment,” carry an estimated 3 million passengers annually in an area from Port Hueneme to Ventura to Ojai.

Thousand Oaks Transit replaced its four diesel buses with alternative-fuel models. Simi Valley Transit will replace half its fleet of nine buses next month and the rest in little over two years.

Once orders for seven new alternative-fueled buses are filled by January 2001, all the buses in those three fleets will be powered by natural gas, save for nine diesel coaches SCAT plans to keep in reserve.

Despite those gains, the county has a long way to go before all diesel-powered buses, a constant source of irritation to motorists and pedestrians choked by clouds of exhaust, are gone.

Ventura Intercity Services Transportation Authority, which uses nine buses to link the county’s cities, has no plans to use cleaner models. Most school districts are sticking with diesel buses. And operators of small transit fleets, including Fillmore Area Transit Corp. with three buses and Moorpark with one, continue to rely on diesel.

Even with substantial government subsidies, some fleet operators say they cannot afford new, cleaner buses. Buses powered by compressed natural gas, the engine increasingly challenging diesel motors, cost about $300,000, 30% more than a diesel model. New fuel stations and added maintenance--the new buses require more care--put the buses out of reach for some.

“It would be a significant expense, even with all the subsidies,” said Maureen Hooper Lopez, director of transit programs for the intercity transportation authority.

Nonetheless, Ventura County has emerged as a national leader in the pursuit of cleaner buses. In all, 61% of the 70 transit buses based in Ventura County are powered by compressed natural gas, or CNG. In 26 months, that proportion is expected to grow to 79% when new buses on order arrive and some fleets shrink, according to officials.

Other major cities in pursuit of clean buses include Sacramento, where two-thirds of the bus fleet runs on clean fuels; Palm Springs, where all diesel buses have been replaced, and El Paso. In the Los Angeles Basin, one in four buses in the Metropolitan Transportation Authority fleet runs on clean fuels.

“They [Ventura County agencies] have been very innovative at coming up with incentives to find ways to get money into alternative-fueled buses,” said Bill Van Amburg, spokesman for Calstart, a nonprofit consortium of companies that promotes alternative transportation technologies. “If all the transit agency buses in Ventura County went to clean fuels, that would be kind of unique. That is impressive. They are among the leaders in California.”

The progress is significant because heavy-duty buses form the backbone of mass transit systems in Southern California and are big smog contributors.

Big buses and trucks comprise 4% of vehicles on Ventura County highways, yet contribute 30% of the gases that form ozone and particle haze, the two most abundant pollutants in Southern California, said Jerry Mason, air quality engineer at the Ventura County Air Pollution Control District.

After nearly a decade of study, the California Air Resources Board in August declared diesel soot a toxic air contaminant, a decision expected to lead to more stringent regulation of diesel fuel and engines. A state-appointed panel of experts concluded microscopic particles in diesel exhaust cause 14,000 cases of lung cancer in California annually, though industry officials contest those findings.

“Diesel buses impact people up and down the streets. Every time one goes by, it assails your senses,” Mason said. “We used to get a lot of complaints on buses, but that’s gone down with the CNG buses.”

Although today’s heavy-duty diesel engines, the kind used in trucks and buses, emit 90% fewer pollutants than those of a decade ago, health and environmental concerns are leading to increased regulation. That is opening markets for cleaner-burning engines.

Vinod K. Duggal, director of advanced engineering for alternative fuels at Cummins Engine Co. of Columbus, Ind., a leading manufacturer of heavy duty natural gas engines, said one-third of all the motors his company sells are natural gas models, up from about 10% three years ago.

Across the United States, one of every five new bus orders are for alternative fuels, Van Amburg said.

“Big cities are concerned about emissions. These engines give us very low emission levels and are quieter than diesel engines,” Duggal said.

Compressed natural gas motors, the most popular alternative engine with fleet operators, emit half as much nitrogen oxide gas and 75% fewer microscopic particles than diesel engines, Duggal said. Both of those pollutants are key ingredients in photochemical smog.

But the new engines are not without problems. In Los Angeles, the MTA has been under pressure from environmentalists to convert its entire fleet of 2,118 buses to alternative fuels. Yet, mechanical breakdowns and repairs are more common in CNG buses, said MTA spokesman Ed Scannell. The agency operates 500 CNG buses, the most in the nation.

“The new CNG’s we’ve got are not all that dependable,” Scannell said.

Peter Drake, general manager for South Coast Area Transit, said the 35 CNG buses in his fleet go through spark plugs, tires and filters faster than diesel engines and require special lubricants. Also, he said, natural gas buses get worse mileage and cannot travel as far between refuelings because they carry less fuel than diesel buses. Natural gas, though, costs about half as much as diesel fuel.

However, Drake said his CNG buses do not break down often because they are made by a different manufacturer. “We’re trying to replace all of our diesel buses with alternative-fueled buses,” Drake said.