From early November 2002 until February 2003, a transit bus plied the streets of Seattle carrying nothing but tanks of water.

Twelve drivers, working in shifts to keep the bus on the road 20 hours a day and seven days a week, racked up 47,000 miles. The water tanks simulated a 130 percent passenger load; the starting, stopping, turning and activating of the vehicle’s wheelchair lift was all meant to push the equipment to the breaking point, if necessary, to test the latest in transit-bus technology: a hybrid drive system much like that in today’s new wave of gasoline-stingy cars.

“I had to kinda peel people off the floor when I told them what I wanted, but I said I needed a year’s worth of data—right away,” said Jim Boon, vehicle maintenance manager for King County Metro Transit. “We did it in 90 days.”

The bus, with its hybrid drive system from Allison, a General Motors division, “never missed a day” due to a breakdown, Boon said. Parts teardowns after the test proved to the satisfaction of him and other Metro Transit officials that hybrid buses deserved to play a role in hauling passengers in the Pacific Northwest.

Now, Seattle leads the country, by a huge margin, in the adoption of hybrid buses. Nowhere—in New York, Los Angeles or anywhere else—does a transit fleet have more than a few. As recently as early October, bus systems such as that in San Joaquin County, Calif., were boasting about the addition of one or two hybrids. Seattle will soon have 235, out of total fleet of 1,390.

Hybrids use less fuel—by GM’s estimate Metro will save 750,000 gallons a year—are quieter and more comfortable. “I’ve had passengers write in to say how much they like the hybrids,” said Metro’s Boon.

But opposite the hybrid’s benefits stands a significant drawback: a 45 percent purchase premium of $200,000, pushing the total cost to a breathtaking $645,000 per coach.

In the automobile world, the price differential for hybrid power plants is modest, perhaps 25 percent for an inexpensive car; less for an expensive one, and shrinking. But where car manufacturers can spread the cost of developing hybrid technology over hundreds of thousands of vehicles, bus manufacturers have no such luxury. In a good year, the transit-bus industry will produce 4,000 buses for this country; Toyota, builder of the hybrid Prius sedan, rolls out about that many non-hybrid vehicles every DAY in its North American assembly plants alone.

That $200,000 is among the reasons that TriMet’s hybrids remain a distinct minority: two in a 650-coach fleet. “We were the firstest but they were the mostest,” quipped Tom Bryant, TriMet’s maintenance director. He was referring to the April 2002 TriMet announcement that it was the first system in the Pacific Northwest to put full-size hybrid-electric buses into commercial service.

TriMet’s test of its two hybrids has shown fuel-economy increases of as much as 23 percent in heavy urban use, and a more modest 9 percent over routes where there are fewer stops. Hybrids use their on-board batteries more intensively at slower, stop-and-go speeds, maximizing economy. Just like hybrid cars such as the Prius, several Honda models and a version of Ford’s Escape SUV, the transit coaches charge their own batteries while on the road. Even with improved economy, however, buses still have single-digit numbers for their diesel consumption. As for the hybrids, “They’re extremely expensive and we are extremely interested in them,” said Bryant. “I would have them in a heartbeat if we could just find a sugar daddy.”

Or sugar momma in the case of King County’s Metro, which benefited from a federal grant, secured by U.S. Sen. Patty Murray, D-Wash., to help with the hybrid purchase.

Yet Seattle’s embracing of hybrid transit coaches is not some general-purpose feel-good campaign. The need for a hybrid, or something like it, grew out of the existence of the city’s 1.3-mile-long bus tunnel beneath the central business district.

Designed to remove buses from surface streets and allow them to travel nearly three times faster, the 1990-vintage tunnel is served by 21 routes and has five stations. But the tunnel would quickly be choked by diesel fumes—or require an elaborate exhaust system – if conventional equipment was put in service there.

The first solution was a 239-bus dual-mode fleet that operates in “hush mode” while in the tunnel. An overhead wire system allowed electric motors to take the place of noisy and smelly diesels, but proved to be a maintenance headache. Those Italian-built Breda buses are wearing out; in their place are the New Flyer hybrids with the GM-designed hybrid equipment. In all, 235 buses have been ordered, 213 for Metro Transit and 22 for Sound Transit. Some 170 are on the job; all are expected to be delivered by year’s end.

But in addition to improved fuel economy, reduced pollution and passenger acceptance, hybrids have longer-term benefits that offset the steep price differential at purchase time, Boon said. Cleaner-running new-generation diesel engines are requiring oil changes every 24,000 miles instead of 6,000. The design of the hybrid system reduces brake wear, increasing brake shoe life from 40,000 miles in a conventional bus to 100,000 miles. “There are tremendous maintenance savings,” said Boon. “I’ve cut 12 percent of maintenance staffing because these buses take less work to keep them on the road.”

Reliability is another benefit that is cutting costs in an unexpected way: when buses break down less often, that allows transit systems to keep fewer spares on hand. By federal rules, no more than 20 percent, or one bus in five, of a transit fleet can consist of spares. Boon thinks he can cut the spares ratio to 12 to 15 percent; as he puts it, “that gives me one free bus out of 20.”

In yet one more way, hybrids cut costs. They accelerate faster and are better able to keep up with traffic. As to how that could possibly translate into savings: “We pay bus drivers by the minute,” said Boon. “They are finishing their routes faster, keeping on schedule better. “When operators clock out after their runs, those minutes add up.

By Boon’s calculations, savings will amount to $200,000 per bus after 8.5 years. After that, he said, the combined savings of the hybrid fleet could amount to $6 million or more yearly.

Theoretically at least, the passenger appeal of the hybrids could allow them to close the gap between buses and light rail. Transit officials have long argued that perceptions about buses—that they are slow, smelly and uncomfortable—turn away passengers who are more than willing to use a light-rail system.

Then again, the answer could lie in technology now being tested in Las Vegas.

The city, with its infamously car-clogged Strip, is betting on what might be called a double hybrid: a hybrid vehicle running over a system that is something of a hybrid of bus and light rail.

Vegas has put $19.4 million into the first U.S. demonstration of the Civis, a hybrid-electric bus manufactured by Irisbus in France. It runs along a route marked by special line patterns, detected by an optical eye above the driver. Steering is accomplished without the driver’s input, relegating his work to braking and accelerating.

Las Vegas, like TriMet, calls its system MAX. At $2.8 million per mile for its seven-mile loop, it costs far more than buses, but far less than the $20 million to $30 million per-mile cost of a light rail system. “This is not your grandfather’s bus system,” Las Vegas transportation official Jacob Snow said at the system’s introduction in June.

Both Metro’s Boon and TriMet’s Bryant said that hybrid buses will not take the place of a light rail system. As in the case of hybrid automobiles, the diesel-electric bus is seen as “bridge” technology that will survive until fuel-cell vehicles, now under intensive development in the passenger-car field, someday become part of bus fleets.

But Jim Boon is convinced that hybrid vehicles have a future as a portion of the Seattle fleet and in his own driveway as well. Not only does Boon drive a Metro-owned Toyota Prius at work, he has owned a Honda Civic hybrid for the past year.  

Tom Ryll is a staff writer for the Columbian newspaper in Vancouver, Wash.

BrainstormNW - January 2005