Thursday, January 14, 2016

Our tips for preparing for the upcoming SR 99/Aurora Avenue lane closures

This stretch of SR 99 looks clear in this picture
but will be extra busy starting Jan. 18,
so start planning now.
By Chelsey Funis

Have you found yourself stressing out about the upcoming SR 99/Aurora Avenue lane closures? From one daily Aurora commuter and transit rider to another, I get you. Four to five weeks of mile-long lane closures south of the Aurora Bridge is going to be a challenge. Which is why we’re asking for help and patience from Aurora travelers.

Roughly 74,000 vehicles per day use this stretch of SR 99 between the Aurora Bridge and the Battery Street Tunnel. That’s like the entire populations of Lynnwood and Edmonds driving to or from downtown Seattle on this section of Aurora every day. During the first phase of lane closures, we’re opening the southbound bus-only lane to all drivers in an effort to balance the needs of cars, trucks and buses; however, we still expect some hefty backups in what is an already congested area.

Because of these expected travel challenges and because there are only so many alternate roads leading into and out of the city, we’re encouraging drivers to plan ahead, allow plenty of extra travel time, and if at all possible, get creative with your commute. Here are some tools to get you started:  
We recognize that the “commuting opportunities” above depend entirely on individuals’ schedules, abilities and circumstances. For some people, these travel alternatives simply won’t work. But if they do, we want to encourage and support you in giving them a try.     

For me, I’m planning to ride my bike to and from work downtown at least three times per week. Hopping on my bike during the dreariest Seattle months is going to be tough, and isn’t for everybody, but I’m looking forward to the challenge.

There are many great commuting resources out there, and a lot of creative, resourceful folks living amongst us. For every commuter that’s able to head out an hour earlier each morning or hop on their bike, there’s an extra space available on the road or on the bus.

Thanks in advance for your patience during this work, and for doing your part to help us minimize congestion.


Bob Sibson said...

Once again, no negotiation! Fait Accompli. Although we have been told I'm not sure the complete story was understood.
You are telling people who commute to and from work on that route that it's going to be highly congested, if not grid-locked for two months southbound and one month northbound.
Of course you realize this will impact every other route in the area, delaying many many more commuters than the 74,000 vehicles you say travel that section of road every day. I really can't imagine how many people are going to be impacted, probably a factor of 2 or 3 at the least.
I would like to understand just why this needs to happen during the day. And if there is no effort overnight it would be one of the cruelest acts on the part of WSDOT in living memory.
I think you need to reconsider this action, it almost feels like someone taking great joy in the bureaucratic halls of WSDOT somewhere, I can almost hear the maniacal laugh to accompany the joy.

Jason Harrison said...

"expect a full bus during peak commute times."

The Aurora Rapidride bus is dangerously over packed not only during peak times, but all hours of the day. It's like a clown car.

Joe said...

Short term construction delays are understandable... however, looking at final construction plans for the for the north end of the tunnel, it appears all southbound traffic on 99 wishing to exit to surface streets before the tunnel (i.e. to south lake union, downtown, Seattle Center, etc.) will be forced into one lane, including exiting buses crossing over from the bus lane on the right to the exit lane which is on the left. If this is true it seems the commute backups we currently experience will be much worse, as now there are 2 lanes to exit east or west on Denny, plus sides streets which allow Seattle Center traffic to exit before Denny. It appears all this traffic will be forced into one exit lane when construction is completed, plus downtown buses crossing over 2 lanes to exit. Please explain how this is expected to be successful.

Michelle Speir said...

Bob Sibson, I'm a contractor who works onsite at a WSDOT office, and while I don't work on this project, I can assure you that there is no maniacal laughter or joy about these closures in the "halls of WSDOT." These are good people who care about traffic woes and safety. Here is a link to more detailed information about the closures:

WSDOT said...

Thank you for your comments, Mr. Sibson. Many of us here at WSDOT and those involved in the planning are North Seattle residents and are part of the travelling public affected by this work. We know that this work will not only be inconvenient but will put additional pressure on the commuting network as a whole. We have been coordinating with SDOT and King County Metro to give travelers timely information so everyone can make informed travel decisions. More information about the work is available on the program website:

Building these sign foundations is an important part of keeping the project moving forward and preparing for the future SR 99 tunnel. This work is being completed during the winter months when traffic volumes are typically lower and there are fewer special events. This work has to be done at some point and delaying the work doesn’t guarantee fewer driver impacts in the future. Regarding work hours, crews will be working nights and weekends in addition to during daytime, in an effort to ensure crews’ safety, minimize impact to drivers by expediting the work, and balance impacts to drivers, buses and nearby residents.

WSDOT said...

Thanks for your questions, Joe. Regarding the future lane and exit configuration for southbound SR 99 north of Denny Way, you are correct – there will be two southbound lanes to the tunnel and one to the off-ramp. State engineers looked at a number of options and configurations for this off-ramp and worked with King County Metro and the City of Seattle on its design. Traffic studies show that the dominant southbound movement in this area is into the tunnel and therefore more vehicles are expected to drive into the tunnel than exit at this location. Additionally, this interchange was designed to maximize throughput within the confines of a constrained right-of-way. Meaning, the width of SR 99 and the space available for the future off ramp, or a second bus-only exit, is significantly limited by private developments on both sides of the highway.

Additionally, it’s important to note that when the tunnel is open to traffic, Aurora Avenue at Harrison, Thomas and John streets will be reestablished with traffic signals to help pedestrians and bikes better maneuver through adjacent neighborhoods. The new intersection at Harrison Street and Aurora Avenue, where southbound drivers will exit, is expected to perform better in terms of wait times than the existing Denny Way intersection and has been designed in a way that will help buses and general-purpose traffic move efficiently through the ramp. Some of the design features include the following:
• The lane assignments and one-lane off-ramp configuration will be signed as far north as the Aurora Bridge.
• The single-lane off-ramp opens quickly into two general-purpose lanes to provide additional vehicle storage at the new Harrison Street intersection, reducing backups onto the off-ramp.
• The intersection also includes a dedicated left-turn lane and traffic signal to more quickly move vehicles headed towards South Lake Union. This, in turn, also helps reduce backups onto the off-ramp.
• A Business Access Transit (BAT) lane will be provided between Harrison Street and Denny Way to improve flow for buses through the new intersections at Thomas and John streets.

If you’d like additional information about the traffic analysis mentioned above, you can review Appendix C Transportation Discipline Report included in the project’s Environmental Impact Statement, available online at

Joe said...

Thanks for responding on the logic for a single lane exit design for city-bound traffic on southbound 99 at the new tunnel entrance. Regarding the new exit strategy, there are a few factors that seemingly complicate the logic of cutting all traffic exiting at Harrison/Denny down to a single lane: 1) Today, cars can exit at the end of the current tunnel (just north of the Market) but I assume once the new tunnel is built, the 1st southbound exit will be in the SODO area. Therefore all those cars will now want to exit at Denny/Harrison, along with the current volume heading to SLU/Downtown/Denny/Belltown. So the volume of cars exiting pre-tunnel will increase. 2) South Lake Union, if you haven't noticed, continues to grow at a fast pace, so if projections were done today rather than a few years ago, the car volumes would be even higher. 3) You may have different data but as a driver I have not generally observed that traffic lights increase throughput. This may happen under certain traffic conditions but it's hard to imagine rush hour traffic is one of them, in particular with thousands of Amazon and other area employees coming down 99 south and needing to head East from the 99 exit ramp.

Regards, Joe

WSDOT said...

Thank you for your follow-up questions, Joe. We’ve forwarded your inquiry on to the Alaskan Way Viaduct Replacement Program technical team and they will respond with more detail soon. In the meantime, if you have additional questions about the program please email them to or call 1-888-AWV-LINE (298-5463).

WSDOT said...

Joe, we were finally able to track down answers to your questions about design of the Harrison/Denny off-ramp.:

1) The traffic data used to develop the Transportation Discipline Report (TDR) from the final EIS took into account the number of people that entered at the Battery Street Tunnel and continued past all downtown exits to continue on towards the West Seattle Bridge. Approximately 60% of traffic on the viaduct does not enter downtown but uses SR 99 to bypass downtown. The remaining vehicle traffic gets off at various downtown exits. The improved functionality of the future Harrison exit over the current Denny exit (more on this below) will handle the expected volume of traffic exiting SR 99 at the tunnel’s north portal. If you’d like to see predicted traffic volumes for SR 99 and the ramps shown graphically, please see the exhibits included in Chapter 5 of the TDR:

2) Traffic demand forecasts for 2015 and 2030 included in the TDR are based on the 2008 Seattle Department of Transportation (SDOT) model, which is an enhanced version of the 2006 Puget Sound Regional Council (PSRC) regional planning model, reflecting assumptions for regional population and employment growth. The traffic forecasts took into account increased downtown employment and population, as well as assumptions regarding completion of Sound Transit Phases 1 & 2, Mercer Street, Spokane Street, and Rapid Ride in 2015. These assumptions have remained generally true.

Additionally, the South Lake Union Transportation Study, South Lake Union Redevelopment Plan and the Bill and Melinda Gates Foundation Campus Master Plan were all included in the cumulative effects traffic analysis.

While the growth of Amazon and other businesses in the South Lake Union area occurred more rapidly than originally anticipated when the TDR was written, traffic volumes for the year 2030 did anticipate South Lake Union growth, based on zoning changes that the City of Seattle implemented. When all the development and transportation improvements are complete, South Lake Union traffic is expected to be similar to the 2030 traffic predictions.

3) One of the goals of the design of the north end of the project is to reconnect the grid at Harrison, Thomas and John streets. This reconnection will facilitate better local movement, including bicycle and pedestrian movement. You are correct that it will take a little longer to get from Harrison to Denny once the tunnel is complete because of the new signals. However, the TDR report from the final EIS found that the future Harrison intersection will result in less vehicle delay than the current Denny intersection. These benefits will come from, among other design features, opening the single-lane ramp into two general-purpose lanes for additional vehicle storage, a dedicated left-turn lane and a Business Access Transit lane between Harrison Street and Denny Way.

If you’d like a greater level of detail, the final EIS and the TDR are among the reports available on the program’s website in the report section:

Thanks again for your interest in the project and inquiries about the project design. If you have additional questions about the program please email them to or call 1-888-AWV-LINE (298-5463).

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