Will Your Next Bus Have Batteries?
They’re quieter and more comfortable, and Seattle leads the
country with its hybrid transit buses. But this new technology doesn’t
By Thomas Ryll
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
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
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
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