She made the comparison in a letter July 11, urging Congress to provide a $500 million federal grant for the $2.44 billion Sound Transit line between Westlake Center and Tukwila.
It was a riposte to Rep. Ernest Istook, R-Okla., who has singled out Sound Transit for particular scorn while launching a broader attack on rail that included proposed budget cuts to Amtrak and urban transit lines. A report from his committee said Sound Transit's 14-mile Link route "provides only minimal relief to the current traffic congestion in the Seattle area," a critique echoed by U.S. Rep. Jennifer Dunn, R-Bellevue, and House Majority Leader Tom DeLay of Texas.
Dorn's seven-lane analogy was repeated in press releases by U.S. Sen. Patty Murray, D-Wash., by Sound Transit and in two newspapers.
Is it credible?
Normally, the Federal Transit Administration (FTA) would not even need to make the argument. Transit grants have been approved routinely in the past, and congestion relief is not among the criteria used to pick projects.
"Is it part of our calculations? No," said FTA spokeswoman Kristi Clemens. "Did we base our recommendation on it? No. It was included in our statement to address some concerns, to solidify what we consider a highly recommended project."
Clemens said her boss was merely trying to help people visualize the number of car trips that light rail would replace.
FTA's endorsement is based on time saved by transit users, the regional land-use patterns and the high local share of the funding. Though Seattle's plans are costlier than most, the predicted ridership in the year 2020 — 42,500 daily trips, including 16,000 by new transit users — is relatively high.
Dorn's math is simple.
When filled, a highway lane can carry 2,100 vehicles in one hour. Seven lanes mean about 14,000 cars, and at 1.1 riders per car, that equals about 16,000 trips.
Similar statements are often made on behalf of projects around the country, said Amy Coggin, communications director for the American Public Transportation Association.
But Dorn's statement contains a number of flaws:
It compares all-day light-rail use to a single hour of highway traffic.
Dorn refers to "peak travel times" — which implies seven lanes of traffic relief for a prolonged period — instead of mentioning "one hour."
Interstate 5 is filled for seven hours a day, not one. Over the course of an entire weekday, the eight general-use lanes and two high-occupancy-vehicle lanes carry almost a quarter-million vehicles at its pinch point just south of the West Seattle Bridge exit.
It compares a 14-mile rail route to one spot on a freeway.
The average light-rail ride is projected to be 5½ miles — not the entire length of the line.
Freeway users make partial trips as well. If every driver who "boards" the freeway between Southcenter and Seneca Street is considered, the quarter-million figure count just about doubles to 430,000 general-lane trips and more than 23,000 trips in the HOV lanes. Passengers in car pools, vans and buses boost freeway ridership to well over a half-million persons a day.
At the busiest point in the light-rail corridor — southbound between Pioneer Square and the Chinatown International District Station — the expected afternoon peak-hour ridership is 3,000 people, counting existing transit users as well as new riders.
Those trips plus northbound riders are enough that Sound Transit could safely compare Link to three freeway lanes.
The first light-rail line and Interstate 5 serve different users.
When transportation officials worry about the "I-5 corridor," they often mean the whole isthmus between Lake Washington and Puget Sound. Light rail was originally advertised as the spine of a regional system, but most trips are being diverted not from the regional freeway but from two Southeast Seattle boulevards.
Lost in the political spin are the real benefits for transit users in Rainier Valley, who can expect a quicker and more comfortable ride.
Trains would reach the valley through a Beacon Hill tunnel, avoiding the bottleneck on Rainier Avenue South between the Chinatown International District and Franklin High School. Sound Transit predicts riders would save 14 to 16 minutes a trip compared with taking buses on Route 42, which parallels the light-rail route on Martin Luther King Jr. Way South.
"It takes about 45 minutes from downtown — that's on a good day," said construction worker Lee Redmond, riding the Route 7 bus as it jerked down Rainier Avenue one evening last week. He believes that Link will be much faster and that it will relieve congestion.
"The light rail would be great. I don't know who would be crazy enough not to want it."
A station at Boeing Access Road was deferred, leaving the Tukwila station as the one most likely to drain off freeway traffic. Park-and-ride users there can avoid taking either Interstate 5 or Highways 509, 599 or 99.
On a regional basis, environmental-impact studies indicate the number of cars entering downtown at the busiest hour, on several highways, would be only 1 or 2 percent fewer with light rail than under a no-build scenario.
John Niles, a bus/rapid transit advocate, said Link opponents will pounce on the seven-lane remark. "We're seeing red," he said. "I find it amazing the administrator of the Federal Transit Administration would just throw out numbers."
But it is also debatable that the light-rail line should be expected to reduce traffic.
The transportation association's Coggin called congestion relief a legitimate issue, "but to reduce the evaluation for an entire transit system to congestion is short-sighted, because there are a number of other benefits to transit — clean air, transportation for people with disabilities, people who are elderly, who don't drive."
"You can't hang the congestion problem on transit," says Gordon Price, a former Vancouver, B.C., city councilman and expert on urban land use. "Nor should transit advocates sell it that way. They're just setting themselves up for failure. It's not going to change the conditions under which congestion was created — too many cars for too little road space."
Sound Transit board member Dwight Pelz, whose district includes the route, has avoided making bold statements about congestion. Instead, he says rail transit encourages urban redevelopment and gives people a good alternative to cars and buses, for less cost than expanding I-5.
The agency also says light rail can keep up with population growth for decades to come.
Board member Cynthia Sullivan, who made a 12-lane comparison on KIRO radio in March, said Friday, "I've told many people I have misstated that."
She says what she meant to explain was that the "theoretical capacity" of light rail equals a freeway, assuming six-car trains that run full every two minutes to Northgate.
Richard Harkness, in a white paper for project opponents, argues that train capacity means less than other issues: how many people will use the line, and is there a cheaper way to move them?
To match an entire freeway, light rail in Seattle would require additional extensions and extreme population densities.
"Ultimately, not in my lifetime, but in my children's, it's going to get to that capacity," Sullivan says.
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Mike Lindblom: 206-515-5631 or firstname.lastname@example.org