Contemplating Montlake

The idyllic scene illustrated above, believe it or not, is supposed to be E. Lake Washington Boulevard as it will look at some point in the future--after the new SR 520 floating bridge has been built and the new westside approaches have been installed. As you can see, there is no traffic.

That’s certainly not what that boulevard looks like today, especially during rush hour through the Arboretum. It makes one wonder what the artist may know that we don’t. The graphic is courtesy of the Washington State Department of Transportation (WSDOT); and as we’ve reported, the State’s “preferred” alternative plan for SR 520 contemplates both the removal of the Arboretum ramps to 520 and the imposition of a new “traffic management” plan for the Arboretum. The combination, apparently, will make Lake Washington Boulevard into the bucolic back road of the artist’s imagination.

Here, by the way, is what the artist imagines the scene at 24th Avenue E. and E. Lake Washington Boulevard will look like (this is the intersection where the bridge to the Museum of History and Industry now crosses 520 at Montlake). Under the “preferred” plan, HOVs may leave Lake Washington Boulevard to enter an eastbound ramp to 520 at about this point. Nevertheless, it doesn’t look like this area is expected to be too busy. Although a bus is depicted, it certainly didn’t end up in that location by coming north on Lake Washington Boulevard, since it would not have been able to navigate under the Arboretum’s low-clearance brick footbridge.

But will smaller high-occupancy vehicles be able to drive through the Arboretum to get to the 24th Avenue intersection? That’s a question that will only have an answer once all the public agencies (State, City and the University of Washington, which co-manages the Arboretum) and the Arboretum Foundation agree on a “traffic management” plan for the Arboretum, as noted by the Governor when she announced the new 520 scheme. It’s a matter of some doubt whether any non-HOV traffic will be able to drive through the Arboretum to access 520 either. Just how traffic will be restricted will soon be a topic of discussion between the various players, with a recommendation on an overall traffic mitigation strategy to go to the State Legislature no later than December 31, 2010.

In the meantime, it’s interesting to speculate on just how that new Montlake Lid and 520 interchange will work exactly, since we’re all going to have to make use of it. Eventually, Montlake will have to handle all of the current traffic that flows into the area plus all of the new traffic that will be dumped there because of the elimination of the Arboretum on and off ramps for 520.

As a starting point, WSDOT had provided me with some additional information concerning current usage of the Arboretum ramps. This graphic depicts usage of the 520 westbound exit to Lake Washington Boulevard in the Arboretum:

And this graphic shows usage of the 520 eastbound entrance:

Perhaps a bit surprisingly, Capitol Hill tops the list of peak-hour users of Lake Washington Boulevard to access and exit 520 (35% of total westbound off-ramp usage and 36% of eastbound on-ramp usage). That includes a lot of people coming down E. Madison Street and turning into the Arboretum rather than taking the more direct (but often more time-consuming) 23rd Avenue route to Montlake. 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, somewhat unexpectedly, are also big users of the Lake Washington Boulevard ramps (23% of eastbound traffic and 13% of westbound).

Madison Parkers (and residents of Denny-Blaine), meanwhile, represent only 5% of eastbound traffic and 4% of westbound traffic. But given the fact that Lake Washington Boulevard is the most direct route to 520 from our neighborhood, it is likely that almost all of Madison Park’s 520 traffic to and from the Eastside goes through the Arboretum. So next to Montlake, which is going to be on the receiving end of a lot of new 520 traffic, Madison Park may feel the biggest impact of any neighborhood when the Arboretum ramps are closed.

Quite clearly, based on this WSDOT data, many neighborhoods—including those as far south as Mt. Baker and Columbia City—are going to negatively impacted by the State’s preferred plan. And if access through the Arboretum is further curtailed, as expected, huge changes to traffic through Madison Valley and down 23rd Avenue E. are inevitable, since that route would become the main corridor for 520 traffic to and from Madison Park, Denny-Blaine, Madrona, Leschi and points south that now utilize Lake Washington Boulevard and enter the Arboretum at E. Madison Street. All of that downtown, Central District, and First Hill traffic that now heads down Madison to enter the Arboretum at Lake Washington Boulevard will in the future probably need to turn left at 23rd for the trip downhill to Montlake.

And when everyone gets to Montlake? Well, WSDOT didn’t provide any graphic of what that’s going to look like!

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