Mercer Mess West: the Update

As we wrote earlier, everyone's attention is now focused on how the city intends to pay for the two-way Mercer fix. Plans for the eastern end of the much-hated roadway are fairly well set, at a price of some $200 million. That's Phase I, from the I-5 ramps to Dexter. But what about Phase II, from Dexter west to Elliott? We love to be long-range pessimists, so we put more questions to the Seattle Department of Transportation. Answers after the jump....

Behold this fragment of a schematic plan from SDOT! But do not hold the city to every aspect of the plan, which is expected to reach final form in June. Many details are still pending. And let's ignore funding for now, to simply concentrate on traffic engineering:


The blue dots indicate the number of lanes in each direction. Valley, which leads to Roy, will still be broken by State Route 99 (Aurora). Unless people are prepared to argue for, and fund, an underpass there. Both Valley and Roy Streets will be two-way, with cars to be steered onto Aurora.

Two-way Mercer proceeds in a three-and-three lane configuration through a substantially widened underpass beneath 99. Also, according to Rick Sheridan of SDOT:

"The widened Mercer underpass will include a 25-foot grade-separated pathway for bikes and pedestrians on the north side of the roadway and a 15-foot sidewalk on the south side."

This means cyclists and pedestrians will still have to jog over from Valley/Roy, the intended lower-speed east-west route for non-motorists. But the trip alongside the motorists in the Mercer underpass should be much safer. (The present sidewalks is dangerously narrow.) Westbound cyclists then have the option of continuing on Mercer, or jogging back to Roy.

As for motorists, there will be a critical segue from three lanes to two at Fifth Ave. N. There, at the western boundary of Seattle Center (where the Lumen condo sits atop a QFC), we can expect a lot of honking, cursing, and merging during rush hour and following major events. Mercer will be two-and-two from Fifth to the Uptown neighborhood (aka LQA). Then, as it is now, one-and-one all the way to Elliott via W. Mercer Place:


Above, motorists will merge from two lanes to one in the vicinity of Ozzie's and the dreaded KFC-Taco Bell.

But let's leap back to the other side of Seattle Center, by Fifth and 99. There, the old diagonal gash of Broad Street will disappear from Fifth to where it presently connects at Valley. This is because the planned new deep-bore tunnel (which replaces the downtown viaduct) will connect directly to 99, removing the need for Broad. Then, per Sheridan,

"To reconnect the street grid south of Mercer St., it will include three new grade-separated crossings of Aurora Ave. N. (SR 99), likely to be at John, Thomas and Harrison Streets."

Again, that determination isn't final, since the tunnel design has barely begun. But the cross streets from Seattle Center (next to the Gates Foundation) leading to South Lake Union will be much more functional, which should absorb some local traffic from Denny and Mercer.

Oh, and just this reminder: Phase II of the Mercer fix is presently scheduled to begin in 2011 (when Phase I is completed, knock wood) at an estimated cost of $76 million. And, again, SDOT expects to show us a plan for Phase II sometime around June.

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