How the waterfront tunnel will save billions and help downtown biking

An advocate for the Tunnel + Transit solution makes his case, along with a plea to the legislature to fund the missing element of promised new Metro Bus service.
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Under the Alaskan Way Viaduct on Seattle's waterfront. (Chuck Taylor)

An advocate for the Tunnel + Transit solution makes his case, along with a plea to the legislature to fund the missing element of promised new Metro Bus service.

On August 2, the Seattle City Council passed a resolution, 8-1, in support of the deep-bored tunnel part of the plan to replace the Alaskan Way Viaduct. The council wants to take advantage of the current favorable bidding climate while also waiting for the bids to come in before a final sign-off with the state in early 2011. Another reason for the two-step approval is to pressure the legislature to authorize appropriate mechanisms for King County to fund the Metro Transit part needed to complete the project as envisioned.

In 2009, the Tunnel + Transit plan, as I'll call it, prevailed as a compromise option. A stakeholders' committee challenged WSDOT'ꀙs odd initial recommendations of either a new elevated viaduct or the "surface + transit option" (no viaduct and no tunnel) as the only two choices for replacing the rickety old Viaduct. Neither of these state-supported options would achieve the primary goals of the majority of the stakeholders: maintaining capacity and reconnecting the city with its waterfront without severely impacting the regional economy. That led to the current bored-tunnel plan.

What both those short-lived state options would have done was to take the Viaduct out of commission for the duration of construction or to eliminate it altogether. Big problem! In 2006, a study by Hebert Research found that even a partial closure of the Alaskan Way Viaduct on SR 99 would cost our regional economy $2 billion a year and 20,000 jobs. Full closure, without a replacement, would cost the regional economy $3.4 billion a year and 32,000 jobs.

Therefore, building a new elevated structure would have cost the local economy $8-13 billion additional to the cost of the project, due to the four years it required to tear the structure down and replace it. The surface option would cost us $3.4 billion per year indefinitely, assuming the accuracy of the Hebert findings. Champions of these two options have been attacking the tunnel because of potential cost overruns, ignoring the guaranteed financial impact of their preferred solutions.

All surface options made the downtown as a whole a worse environment for bicyclists.

Furthermore, in 2008 the "Urban Quality Evaluation" by Gehl Architects of Copenhagen, internationally respected experts on pedestrian-friendly design, evaluated all eight of the proposed options being considered at the time, examining the effect of traffic on the pedestrian realm. Excluding the elevated structure that is inherently unfriendly to pedestrians and the waterfront, only the 'ꀜdemand-management option'ꀝ had better traffic levels on downtown streets than the bored tunnel option, and all surface options made the downtown as a whole a worse environment for bicyclists.

'ꀜThe less vehicle traffic on the surface, the better,'ꀝ Gehl found. 'ꀜA double-edged strategy is called for: get traffic underground and start lowering traffic volumes on the surface. Discourage more vehicular traffic and invite more people to walk, bicycle, and take public transportation.'ꀝ

These are all good reasons that we need to fund the transit portion of the Tunnel + Transit plan, as was promised to former County Executive Ron Sims to get his support of the governor's ultimate recommendation. That promise is unrealized, and the legislature has so far brushed it aside. Without enhanced Metro service, which the new tax would allow, we invite more traffic, gridlock, and a less friendly pedestrian and bicycle environment on the waterfront.

For these reasons 90 percent of the stakeholders recommended that an option be presented that would achieve their primary goals without causing the economic impact even a temporary loss of the structure could bring. The only option that could achieve this was Tunnel + Transit, which:

  • Allows the current Viaduct to remain during construction, minimizing economic impact during construction.
  • Mirrors underground the current function of the Viaduct without adding capacity, allowing 60,000 vehicles to pass through the city while another 50,000 are displaced to transit or access the city from various points immediately north and south of downtown, and directly from Alaskan Way similar to the current off-ramps.
  • Minimizes vehicular impacts to city streets especially in Pioneer Square, and Belltown, preserving parking and bicycle lanes along Second and Fourth Avenues.
  • Creates 9 acres of new open space along the waterfront, and minimizes waterfront traffic levels.
  • Improves the city fabric and pedestrian environment in Belltown, where existing SR 99 ramps will be removed.
  • Reconnects South Lake Union and Lower Queen Anne along John, Thomas, and Harrison Streets. This will be the first time in 50 years pedestrians will be able to walk from the Cascade neighborhood to Seattle Center on pedestrian-friendly streets.
  • Invests $190 million in new transit options.

That last point indicates the work that still needs to be done. In the legislative sessions ahead the Tunnel + Transit Coalition will encourage legislators to grant King County Metro the authority to raise funds to preserve and increase transit service. Likewise, we expect that the Seattle City Council will find a rational mechanism to fund the seawall replacement.

Architect Daniel Burnham once wrote, 'ꀜMake big plans; aim high in hope and work, remembering that a noble, logical diagram once recorded will not die.'ꀝ The logical diagram for Seattle is the Tunnel + Transit plan.


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