A new mega-tunnel won’t save Seattle from the tyranny of traffic.
By Ben Goldfarb, February 27, 2015
Along the Seattle waterfront, beneath 60 feet of earth, lies a monument to human ingenuity. Her name is Bertha, and she’s the biggest tunnel-boring machine ever built: longer than a football field, heavy as the Eiffel Tower, endowed with a tooth-studded face five stories tall. Like a giant earthworm, she can chew through dirt and eject it as slurry; in good soil, she’s capable of digesting 35 feet per day. On one of her Twitter accounts (@BerthaDigsSR99), she has over 14,000 followers. She is, in every respect, a marvel, come to rescue Seattle drivers from an unsafe and unsightly elevated freeway.
There’s only one problem: She’s broken.
Bertha’s saga began in 2001, when an earthquake damaged Seattle’s Alaskan Way Viaduct. In 2009, city and state leaders agreed to replace the perilous viaduct with a 2-mile-long double-decker tunnel. Such a tunnel would require a custom-built machine, and on April 2, 2013, Seattle’s mechanical savior arrived on a barge from Osaka, Japan. “Nice place you’ve got here,” Bertha tweeted. “I was expecting rain.”
As it turned out, Bertha would be the one who needed saving. On Dec. 3, 2013, she hit a steel pipe; soon after, she overheated. Workers eventually discovered that the bearing seals on her face had suffered damage. Bertha ground to a halt, 1,023 feet into an 8,000-foot dig.
More than a year later, Bertha has barely moved another inch, the timeline for completion has been pushed back 20 months, and Seattleites are restless. The viaduct is still standing, shaky as ever.
Buildings in nearby Pioneer Square have settled and cracked, perhaps as a result of attempts to rescue the stalled drill. In January, two Republican state senators introduced a bill that would kill the $4.2 billion project altogether. “We can’t just continue to pour billions of dollars into a hole with no sign of success on the horizon,” said Spokane’s Michael Baumgartner, one of the sponsors.
Bertha’s proponents argue that if the viaduct comes down without a highway to succeed it, all those displaced vehicles — up to 110,000 per day — will worsen the city’s already nightmarish gridlock. But growing evidence suggests the relationship between highways and traffic doesn’t work that way. To the contrary: If you don’t build highways, the cars won’t come.
Imagine living in Los Angeles. Once a week, you shop for groceries at a pricey supermarket two miles away. You could save money at the Walmart 10 miles down the highway, but with traffic that becomes a half-hour trip. So you stay close to home.
Now imagine that the city adds an extra lane to the highway. Surely, you think, the traffic will dissipate; now it’s worth driving to Walmart. But you’re not the only one obeying that logic. Once the road is expanded, more folks use it to shop, visit relatives, go out to movies and restaurants. Soon, the highway is as clogged as ever.
That’s exactly what happened when L.A. opened an expensive car-pool lane on I-405 last May. Four months later, traffic was a minute slower than it had been before. Economists call this phenomenon “induced demand”: Build more roads, and people will drive more. “What’s interesting is that traffic increases in almost exactly a one-to-one relationship with road capacity,” says Matthew Turner, an economist at Brown University and author of a 2011 paper called The Fundamental Law of Road Congestion. “You cannot build your way out of problems.”
Back in the mid-2000s, many community leaders argued — and still argue — that Seattle didn’t need to replace the viaduct. Improving surface roads and transit, they said, would be cheaper, safer, and more compatible with greenhouse gas reduction goals. But the so-called “surface/transit option” never got far. Abandon the highway, then-Gov. Christine Gregoire said in 2009, and “you can shut down business in Seattle.”
Seattle’s traffic is undeniably terrible — the fourth-worst in the country. Yet driving rates in Seattle and Washington state have largely been stagnant — and, in some places, falling — for over a decade. National rates have also dropped every year since 2004. The trend is probably generational: Young people drive far less than their parents did. “Bertha, to me, is a failure of imagination,” says Clark Williams-Derry, deputy director of the Sightline Institute, a Seattle sustainability think tank. “It comes from a mindset that can’t conceive of a world in which traffic volumes might be falling.”
Eliminating highways could help expedite driving’s decline: According to one review, up to 25 percent of traffic simply disappears when road capacity vanishes. In the aftermath of the 1989 Loma Prieta earthquake, and the fatal, seismically induced collapse of the Cypress Street Viaduct, San Francisco decided to tear down two elevated highways, the Embarcadero and Central freeways, and replace them with surface boulevards. The much-feared congestion crises never materialized. As it turns out, even improving public transit has little influence. Only downsizing roads can change driving habits.
Nonetheless, Bertha will almost certainly survive: Too much money and too many reputations are at stake to entomb her now; the bill to kill the project didn’t receive so much as a hearing. Bertha recently began crawling toward an access shaft, from which a crane will hoist her head to the surface for repairs. “There’s really no fiscally prudent course other than the course we’re on,” Gov. Jay Inslee said recently.