Arboretum to no longer be gateway to Eastside

Those who appreciate the Washington Park Arboretum principally for its role as a freeway-access point will soon need to start valuing it for its other virtues. The arboretum’s on- and off-ramps to state Route 520 will be demolished as a result of the governor’s recently announced “preferred plan” for the western approaches to the new floating bridge.
For the many residents of Madison Park, Madison Valley, Madrona, Leschi and other neighborhoods who currently utilize Lake Washington Boulevard as their portal to and from the Eastside, the new way to access 520 will be this: drive to Montlake and get in line.

You can chalk this up as a big win for the arboretum, the University of Washington and the City of Seattle, who jointly opposed the state’s previous plan, Option A+, which had included the construction of new, bigger and wider 520 ramps within the arboretum — that idea is now out. As early as 2012, the arboretum’s westbound ramp from 520 will be shut, and assuming construction goes according to plan, the eastbound ramp to 520 will be removed in 2015.

Sidestepping the arboretum
In making her announcement, Gov. Christine Gregoire said that the state “heard the concerns of the neighborhoods and the City of Seattle” and created a new design for the floating bridge and its western approaches to address those concerns. With regard to the elimination of the Lake Washington Boulevard ramps, the governor said, “The purpose is to protect the arboretum.”

Opponents of the state’s new plan, however, say that an average of 15,000 vehicles use the arboretum ramps each day, and throwing all of that traffic into the Montlake neighborhood will simply exacerbate an already difficult traffic situation there.

“The neighborhoods got shafted,” says Fran Conley, of the Coalition for a Sustainable 520, which opposed Option A+ and now opposes the new plan.

The State Department of Transportation (WSDOT) claims that the newly designed Montlake interchange will be able to smoothly handle the increased traffic flow. But getting to Montlake from neighborhoods to the south will probably become more difficult than it is today, since the governor also announced that the state and city will work with the UW and The Arboretum Foundation on ways to reduce traffic through the arboretum. The city and the UW jointly manage Washington Park Arboretum.

WSDOT reports that some of the details are still being worked out, but when the new Montlake interchange is completed, traffic that now enters 520 in the arboretum will channel to the intersection of Lake Washington Boulevard East and Montlake Boulevard East, where it will (after negotiating at least one traffic light) enter a freeway entrance that loops around and under the Montlake Lid, heading eastbound.

As it stands now, traffic from Lake Washington Boulevard attempting to go west on 520 will need to negotiate both a right turn at the same intersection with Montlake Boulevard and then make a left turn through another traffic light a block farther north. But there will be no U-turn required, as there is now.

There may be some relief for high-occupancy vehicles (HOV) whose drivers want to go eastbound on 520, however. HOV drivers will be allowed to enter the freeway by making a right turn onto 24th Avenue East from Lake Washington Boulevard (where the bridge to the Museum of History & Industry crosses 520) and then enter the HOV lanes eastbound.

The same would be true for the westbound HOV lane from 520, which will have an exit ramp leading to the 24th Avenue intersection with Lake Washington Boulevard.

Impact points

But with access through the arboretum on Lake Washington Boulevard potentially curtailed, how many vehicles will benefit from being allowed to use this more-direct route? That question can’t be answered until the negotiations over limiting arboretum traffic have been concluded, and a study group is apparently just beginning work on a traffic management plan.

WSDOT has analyzed which neighborhoods will be most impacted by the elimination of the arboretum ramps. Perhaps a bit surprisingly, Capitol Hill tops the list of peak-hour users of Lake Washington Boulevard to access and exit 520 (35 percent of total westbound off-ramp usage and 36 percent of eastbound on-ramp usage).

First Hill and the Central Area (including Madrona) comprise the next biggest number of westbound off-ramp users. Many of these drivers are certainly bypassing the more direct route to and from their neighborhoods. Montlake residents are also big users of the Lake Washington ramps (23 percent of eastbound traffic and 13 percent of westbound).

Madison Park residents, meanwhile, represent only 5 percent of eastbound traffic and 4 percent of westbound traffic. But given the fact that Lake Washington Boulevard is the most direct route to 520 from the neighborhood, it is likely that almost all of Madison Park’s 520 traffic to and from the Eastside goes through the arboretum.

Not a ‘done deal’ yet
The Coalition for a Sustainable 520 believes that the new “preferred plan” the governor announced is far from being a done deal. Funding, for example, has only been identified for approximately $2.6 billion of the expected $4.6 billion cost.

At this point, though, there is certainly enough funding to cover the replacement cost of the 520 floating bridge. Construction is scheduled to begin on that in 2012 and take about two years. Tolling on the existing bridge will start next year to help pay for bridge replacement.
And if the funds are found, construction of the “preferred plan” for 520’s western bridge approaches could begin sometime in 2015.

This is an updated and expanded version of a story that originally appeared on[[In-content Ad]]