On the seventh anniversary of the Nisqually earthquake, members of the Alaskan Way Viaduct Stakeholders Advisory Committee heard presentations on the current use of the viaduct, and about improvements which can be made to surface streets and to I-5, two more building blocks of any packaged solution for the central structure.

At the meeting Thursday, Feb. 28, Jim Parsons, lead independent project manager for the project, described current conditions.

Seattle is built on an isthmus, and downtown is a bottleneck.

"An hourglass within an hourglass," he said.

Hills, ridges, lakes and Elliott Bay narrow possible routes north-south. Traffic is hampered by broken and colliding street grids, and the placement of Seattle Center, the stadiums, Aurora Avenue and I-5.

The Alaskan Way Viaduct, completed in 1953, was constructed as a bypass, carrying drivers on SR-99 around downtown. The exit at Seneca, and the entrance at Columbia, were added later. Ironically, today the viaduct is mostly used for local access to neighborhoods close to downtown.

On weekdays, 56,100 vehicles use the viaduct northbound: Almost half, 27,900, enter from East Marginal Way; 16,900 from the West Seattle bridge; and 11,300 from First Avenue South at Qwest Stadium. In the mornings, less than 30 percent of this traffic continues to north Seattle.

Of the 55,000 vehicles using the viaduct southbound, almost a third, 17,900 enter from Aurora Avenue; almost another third, 17,100, from Elliott Avenue; 10,300 from South Lake Union and Seattle Center, and 9,700 enter at Columbia Street. In the mornings, 37 percent of these trips continue south of Seattle.

Traffic on both the viaduct and I-5 doubled since 1975, peaking in 1999. Since then, despite increased population and employment downtown, traffic numbers have held steady.

Parsons explained that I-5 has reached saturation, unable to carry more traffic. The freeway was designed to provide access to the central city, but is used primarily for through traffic, the opposite of the viaduct. Congestion starts at 6 a.m. weekdays, and lasts through 7 p.m. - 9 p.m. southbound.

The viaduct still shows distinct morning and afternoon peaks in traffic. It could carry more vehicles, but traffic hasn't increased there in eight years either.

More people are using transit, Parsons said. The 2000 Census shows Seattle has the highest percentage of transit users of any U.S. city without light rail. At 40 percent, it beats many comparable cities such as Portland, that do have mass transit. During the morning commute, half of the trips people take to downtown are on transit.

Next, Carol Hunter, from the Washington State Department of Transportation, continued her presentation from the January meeting about upcoming construction on I-5.

Last August was just a taste, she said, when pavement was replaced from Spokane Street to I-90. Starting in 2009, road crews will diamond grind 68 lane-miles of freeway surface, from the Boeing Access Road to the Snohomish County line, as a temporary fix. In 2017, the state will begin replacing 100 lane-miles of pavement, currently 20 years past its expected life. Nine inches of concrete will be torn out and replaced with 13 inches reinforced with dowel bars.

New designs will alleviate choke points, said Hunter. Some entrances and exits downtown may be closed, bus lanes added. Express lanes may be converted to include both directions. High occupancy vehicle (HOV) lanes may be upped to three-person carpools.

This may be a chance to fix the traffic stopping "weave and merge" between 45th Street entrance, SR 520 and Mercer Street exit.

Hunter was most optimistic about active traffic management, a technology already used in Europe. Electronic signs above each lane change depending on traffic conditions: closing lanes blocked ahead by a collision, or lowering speed limits, which can actually increase the number of vehicles getting through.

The state's Moving Forward projects include $25 million to install electronic signage between Spokane Street and I-90 in 2010, before construction begins on the south end of the viaduct.

Gene Hoglund, representing Working Families for an Elevated Solution on the advisory committee, expressed concern about construction on the viaduct overlapping with work on the freeway, doubly crippling traffic.

"Shouldn't we leave the viaduct until after I-5?" he proposed.

"No," said Dave Dye, deputy secretary for the Washington State Department of Transportation, running the meeting. "The safety principle drives 99 to be first. We'll have many of the pieces in place for 99 before the I-5 repaving."

Last, Steve Pearce, from the Seattle Department of Transportation, continued his presentation from January on the city's Urban Mobility Plan.

Last March, city residents voted against an elevated structure and against a tunnel to replace the viaduct. Mayor Greg Nickels asked the city's department of transportation to study a surface-transit-only option for the waterfront and improvements to downtown streets to support it. Originally an independent project, the Urban Mobility Plan has been brought to the viaduct advisory committee as another building block toward a solution for the central viaduct.

"It was developed as the surface-transit alternative," Pearce said. "But we could use these ideas in any hybrid alternative. They are available as a palette of alternatives."

Pearce, the manager for the Urban Mobility Plan, said, unlike the monolithic I-5 construction, the plan is many small projects to improve traffic.

Ideas include: converting Mercer Street to two-way; reconnecting South Lake Union to Seattle Center by putting in cross streets and lights on Aurora; removing parking on First Avenue through Pioneer Square; adding lanes to Second and Fourth Avenues through downtown; building an overpass at South Lander above the train tracks; adding more street car lines, from the stadiums to Seattle Center, from First Hill to Broadway.

Many ideas have trade offs: New streetcar lines will eliminate lanes for cars. New bus lanes eliminate downtown parking.

Some projects are already in progress. Construction begins this year on a new exit from the Spokane Street viaduct to Fourth Avenue South, part of a project to widen that viaduct to six lanes between the West Seattle Bridge and I-5.

After the meeting, few committee members stayed to examine presentation boards in the adjacent room. Staff remained to answer questions about the Moving Forward projects - work already started by the Washington State Department of Transportation on the northern and southern sections of the viaduct, and four of its piers in Pioneer Square damaged by the Nisqually earthquake - and on the SR-519 project, which extends I-90 exits and builds new ramps around the stadiums.

At the meeting March 27, the committee will learn about Metro and Sound Transit projects, as well as changes to land use and government policies, as additional building blocks toward a viaduct solution.

In April, committee will finally hear about the alternatives proposed to replace the central structure of the Alaskan Way Viaduct. The directors purposely saved the viaduct discussion for last.

"We all have strong opinions on 99," Parsons told the committee in January, "but you may not know what's going on elsewhere. This way you're up to speed on everything else."

The next set of open meetings for public comment will be in May.

Matthew G. Miller may be reached via wseditor@robinsonnews.com