January 29, 2013  2:05 PM

Suburban transit a key piece of tailpipe emissions study

Every day, about 550 members of Sherwood's 6,800-person workforce go to work in nearby Tualatin, four miles east. Another 400 go to work in Wilsonville, six miles away.

There's no question about the easiest way to get to either jobs center from Sherwood, a Washington County suburb of about 18,000 residents: It's in a car, on any of the former farm-to-market roads that are increasingly lifelines to suburban workers.

Let's make some other assumptions: People choose to drive because it's the best available option for them, and that cars aren't the most efficient way to move people, at least in terms of the space they use and carbon they produce.

Editor's note: Climate Futures series

As Metro's planning staff looks at ways to address a state mandate to reduce tailpipe emissions in the Portland region, Metro News is digging into some of the 144 ideas under study. Our goal is to paint a picture of what the Portland region could look like if any of those scenarios are adopted.

Please note that Metro planning staff is not responsible for this content. Comments on the content should be directed to Metro News at 503-813-7583 or newsroom@oregonmetro.gov.

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How do the people of the region – particularly in far-flung suburbs where transit service is minimal and car is king – reconcile those two?

That's a critical question if transit ridership is to increase, one of the ways the region could address a state mandate to reduce tailpipe emissions in the Portland area.

Suburban hurdles 

One of the reasons transit ridership is so high in Portland proper is because it's omnipresent. Workplaces, stores, after-work errands and frivolity – they're all close to transit lines that run with some regularity.

Transit connections

Transit connections

See how the region's centers are connected via transit

View the full graphic (PDF)

But those connections that make Portland a good place to ride a bus simply don't exist beyond the core of the city.

A bus trip from Sherwood to Tualatin can take an hour. So does a commute to Wilsonville. A bus ride to Portland is only 40 minutes during the morning rush hour, but can be more than twice as long after 8 a.m.

All of those journeys route through Tigard, the hub of transit in the south metro area.

Transit ridership in the suburban town centers – places designated by cities and Metro as areas of more intense development – tend to drop as you move out from the city center. But there's also a correlation between transit ridership and the number of transit lines connecting those centers to others.

Hillsdale, for example, has 1,222 transit boardings daily, or 4.6 for every 10 employees and residents in the town center area. Milwaukie has 3 boardings for every 10 residents and employees; each has 12 direct bus connections to other town or regional centers.

View a map of ridership by TriMet stop (data courtesy Portland Afoot)

Centers with more than six connections to other centers have double the transit ridership of those with five or fewer. Boardings are tripled in centers with more than seven direct connections – 9.4 boardings per resident and employee.

In the Sherwood town center, with its one transit connection (to King City and ultimately Tigard), 1.3 people get on a bus daily for every 10 residents and employees in the area.

The correlation between distance from Portland and ridership is much weaker than the number of transit connections – centers within 10 miles of downtown Portland average 6.5 transit boardings per resident and employee, while those 10 or more miles out average 4.6.

Transit connections

Transit use

See how ridership relates to transit connections between town and regional centers

View the full graphic (PDF)

When TriMet took over the region's transit service decades ago, it scrapped several bus routes running around Washington County, and instead focused its westside service on connecting transit centers, a hub-and-spoke system, said Alan Lehto, the transit agency's lead planner. The trade-off was to run buses more frequently on the lines that survived.

That system could work well for folks who get to work at 8 and leave at 5 to head home.

But life can have as many turns as Hall Boulevard. Think of the reasons you might have to run out at lunch – to check on a sick child, to pick up dry cleaning, to go visit a friend – and those all add up to reasons to pass up on transit as a way to get to work.

The key to broader acceptance, Lehto said, is removing that doubt.

"Imagine if all the people who live within walking distance to frequent service could, all the time, walk out their door and know a bus is coming," he said. "That's a transformative experience for a lot of people. All of the sudden, a whole new way of moving becomes real to someone."

That's only the case in a few places around the Portland region – only five of TriMet's 79 bus lines average more than four trips an hour between 8 a.m. and 7 p.m., and only one of those averages more than five trips an hour during the day.

Money matters

It's all a moot point if the region's main transit agency can't afford it.

TriMet has spent years cutting service to cope with soaring outlays for capital expenses and employee benefits. In its 2012-13 fiscal year, TriMet expected to collect $477 million in revenue, $115 million of that coming from rider fares.

It budgeted $22.6 million from its general fund for capital costs for project construction, and $57.5 million to cover employee pensions.

"We need a way to fix that, whatever that is," Lehto said of the pension expenses.

Regardless, it costs TriMet $129 an hour to run a bus.

Jarrett Walker, a Portland-based planning consultant, said TriMet would need a major new funding source – one more stable than the payroll tax, which covers about half of its revenue – to offer more service around the region, whether it's between the suburbs or increased frequency in neighborhoods.

"TriMet may succeed in stabilizing itself at something like its current service levels, but it is in no position to achieve a substantial service expansion without a major new funding source, which should be a more stable source than the current one," he said.

As part of its state-mandated Climate Smart Communities project, Metro is studying how much an increase in transit ridership could impact tailpipe emissions in the region. Initial studies of that are looking at increasing transit service as a way to increase ridership.

In 2010, the Portland region had nine miles of transit service per capita; the region's current transportation plans call for a tripling of that by 2035.

How much of a dent in carbon emissions would the region make if the region's buses and trains offered 69 miles of service per person? What about 115 miles per person, on par with New York City?

Those are some of the 144 scenarios being studied as part of the climate project.

Transit and greenhouse gas

Even if costs weren't an issue, though, people still need to ride for transit service to eat away at carbon emissions. Juan Matute, a professor studying climate change at the UCLA Institute of Transportation Studies, said it's better for the environment for people to drive than to travel on a near-empty bus.

A recent study by UCLA and Arizona State University researchers found that it takes about eight people per bus, or 13 per light rail vehicle, to shift from car to transit to have net greenhouse gas benefits.

Those benefits could be exponential.

Matute said there's an indirect benefit to improving transit ridership across the region – it'll make trips shorter for people with cars, too.

"Because transit reduces the need for parking and road space, it makes it possible to fit more destinations in a given area," Matute said. "Because there's less distance between origins and destinations, even cars will travel fewer miles than they would have if the region were less dense."

Metro News editor Nick Christensen can be reached at nick.christensen@oregonmetro.gov or 503-813-7583. Follow Metro on Twitter @oregonmetro.

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