All viaduct options are unfriendly to pedestrians, study finds

None of the eight options for replacing the Alaskan Way Viaduct would be friendly for pedestrians, according to a new study to be released today.

The study found flaws with the surface, tunnel and aerial options and said none provides a "positive pedestrian" environment that would tie downtown Seattle to its waterfront.

The authors of the 40-page report, Gehl Architects of Copenhagen, were asked to find ways to get more people to walk and bicycle along the waterfront, to increase the amount of time people spend in the city and to increase the potential for new activities on the waterfront, such as outdoor events.

What the city needs to do, according to the report, is discourage cars and get more people walking, bicycling and taking public transit.

The state and the city of Seattle, which are spearheading the replacement project, have never denied that it would like to reduce traffic volumes, but say it may be impossible in a traffic corridor that now carries 110,000 vehicles each day.

Here's how the study rates the various plans for pedestrian use:

• The three surface proposals: "The space along the water is out-of-scale, too wide and lacking definition. The waterfront will be a vehicle-dominated place with traffic volumes between 30,000 and 51,000. People will not be invited to engage in recreational activities along the water."

• The four-lane elevated viaduct: "An unattractive space created under the two elevated highways, creating problems similar to today's situation. Traffic on Alaskan Way will more than double."

• Integrated elevated option proposed by State House Speaker Frank Chopp: "Unattractive spaces are created on top of the elevated structure," an area that would be unsafe and unattractive and likely to remain unused by pedestrians or bicyclists."

• Four-lane bored tunnel: A tunnel under Western Avenue would leave the waterfront open, but as in the surface proposals, the waterfront would be too wide and out of scale for pedestrians.

• Cut-and-cover tunnel: While this type of tunnel leaves the waterfront open, it too would create a space that would be too wide for pedestrian use.

• Four-lane lidded trench: The option doesn't create as open a waterfront as do some of the other tunnel plans, and a ventilation shaft in the middle would be disruptive visually and create noise and pollution.

The report also rates streets in terms of the traffic they would carry.

A "great" street would carry only 1,000 cars a day; a "good" street would have 5,000 cars; a "bad street" would have 50,000 cars a day and would not be "fit for pedestrians."

"This is a once-in-a-lifetime opportunity to develop a vision for the city on a new level," according to the report. "To create a better life demands the big question: What do we want the city to be. If the answer is a fine city for people, then traffic capacity cannot be increased and thinking cannot center on vehicles."

State's open-space report

In other developments, the state just released a comparison of how much open space each of the eight options would provide.

A report issued by the state Department of Transportation found the waterfront promenade would increase from an average of 20 feet to between 40 and 106 feet wide. All, except for the elevated options, would open up the waterfront to improved views, visibility and sunlight.

As for total open space, the three surface options would provide between 8.7 and 11 acres; the four-lane elevated, 9.2 acres; the integrated elevated proposed by Chopp, 21 acres; the deep-bore tunnel, 11 acres; the cut-and-cover tunnel, 11.6 acres; and the lidded trench, 8.4 acres.

The report found one surface option and two tunnels minimize the amount of traffic on the waterfront as compared to the other alternatives.

The four-lane elevated is a slight improvement over the existing viaduct, but the amount of open space is smaller than the surface and tunnel options, and the noise is higher.

Chopp's plan "is the least desirable option from an urban-design and open-space standpoint," the report found. It said it is worse than the existing viaduct because it provides a lower quality of public space and compromises the historic identity of the waterfront and access to it from downtown.

Susan Gilmore: 206-464-2054 or sgilmore@seattletimes.com