Thursday, January 7, 2016

New SR-520 Lake Washington Ramp Starts Today, SDOT Still Monitoring Montlake Traffic Flow

Yesterday a new SR 520 westbound off-ramp to East Lake Washington Boulevard opened and the existing off-ramp in the Arboretum closed.  Drivers are being channeled onto 24th Avenue NE to go southbound on Montlake.
In August, the Montlake Boulevard exit was also closed and re-routed. Following the change, the Laurelhurst Blog Staff received emails from drivers frustrated at the wait time at the light of the Montlake exit.
The Blog Staff contacted WSDOT who said they were working with the City of Seattle to monitor traffic conditions and adjust signal timing on Montlake Boulevard as needed.
Kristin Sandstrom, Communications with WSDOT, added that they had passed the community observations to WSDOT and SDOT engineers.
Kristin said: 
We are aware of the traffic delays and backups the signal initially caused, and have responded to more than 70 individuals who contacted us about it via email, phone and Twitter during the first week that the signal was in place. Since then, we have seen improved operations and have heard some positive comments from drivers.   
Adjustments have already been made to the signals in the Montlake area. SDOT’s initial adjustment during the week of Aug. 10 aimed to reduce congestion on the eastbound SR 520 off-ramp to Montlake Boulevard; the signal change resulted in decreased backups on the eastbound off-ramp.   
SDOT further adjusted the signal timing during in mid-August to balance and minimize queues, primarily along northbound Montlake Boulevard. Based on our field observations and the public feedback we’ve received since then, traffic conditions at the interchange have improved significantly.  We’re still working on balancing the system and we recognize that certain intersections are still experiencing increased congestion.  
SDOT will continue to monitor traffic in the area and further adjust signal-timing as necessary to improve traffic conditions even more on Montlake Boulevard and the SR 520 on- and off-ramps 
As you may know, it’s a delicate balancing act to keep traffic moving both on the SR 520 highway and on local streets. A key reason for the new signal is to enhance safety for bicyclists and pedestrians. Our goal is to realize that safety

Kristin also said that WSDOT, in partnership with the Seattle Department of Transportation (SDOT), completed traffic studies in 2012, prior to West Approach Bridge North construction that included modeling the addition of a signal at the end of the westbound off-ramp.

She said:
The plans developed based on this study determined that the new signal would not have a noticeable effect on the Montlake interchange’s level of service. I
t is common practice to monitor traffic patterns after the introduction of a new signal, in case adjustments need to be made. This is due diligence regarding traffic operations—separate from analysis in previous studies.  WSDOT’s and SDOT’s recent assessment of traffic patterns revealed that traffic volumes from Montlake Boulevard to SR 520 on-ramps have increased since 2012.  
The city’s population growth may underlie the increase in traffic. Another contributing factor that may account for the increased congestion in the area is the expected adjustment period as travelers adapt to the new traffic signals and patterns.  
SDOT is actively and continually monitoring traffic through field observations and traffic cameras. SDOT traffic engineers use this information to make changes to signal timing in the area. There will not be any formal publication of a new “traffic study” – the changes SDOT makes will be the outcome of this continuing observation and analysis.

She said the new traffic signal was installed to improve the merge point for drivers exiting westbound SR 520 and turning north onto Montlake Boulevard, as well as improve safety for bicyclists and pedestrians traveling through the Montlake area.

SDOT can be contacted via phone, email or Twitter with questions or concerns.

Here is a post last week from the Madison Park Blog regarding the demolition of the "ramps to nowhere" and the new exit:

SR-520 Arboretum ramps finally coming down
Posted: 30 Dec 2015 12:55 PM PST

Western exit from 520 to be replaced January 6

It's been well over five years since Madison Park first learned that the Arboretum ramps to and from the 520 floating bridge would ultimately be just a memory (see our May 2010 posting on that subject here.)  Next month, the neighborhood will begin to see the consequences, for better or worse, of this historic highway reconfiguration. The Westbound 520 exit to Lake Washington Boulevard will be permanently closed on January 5 at 11 p.m. Beginning at 5 a.m. on January 6, drivers wishing to exit 520 to head South at Montlake will need to use a new Westbound ramp to Lake Washington Boulevard, which will channel traffic onto 24th Avenue E. (as shown below):

At least initially, there will be two stops associated with this exit, one at 24th (to allow construction vehicles easier access to a staging area) and one at Lake Washington Boulevard, which will be permanent.  Drivers may turn either East or West onto the Boulevard, which will be a new four-way stop at that point.  For those interested, here's a nifty traffic animation from WSDOT showing how this will all work.

As most readers will recall, WSDOT has had its issues with the new exit ramp from 520 to Montlake Boulevard, which opened earlier this year.  WSDOT is already noting that "as drivers adjust to the new [Lake Washington Boulevard] off-ramp, WSDOT will work with the City of Seattle to monitor traffic conditions and adjust signal timing on Montlake Boulevard as needed."

Ultimately, all of the Arboretum ramps will be outta here, of course:

The contractor has already demolished part of the "Ramps to Nowhere" configuration (a remnant of the never-built R.H. Thompson Expressway) and the final removal of these unconnected ramps is expected to be completed by the end of Spring 2016, according to WSDOT.  Meanwhile, no firm date has been established for removal of the existing Eastbound entrance ramp to 520 from the Arboretum.  This will happen no earlier than the fall of 2016, though more likely in 2017.  

The Westbound ramp needed to be replaced now because it is in the path of the new SR 520 West Approach Bridge North, which will connect the three Westbound lanes of the new floating bridge with 520 in the Montlake area:

Completion of the new approach bridge is scheduled for the summer of 2017.

 Here is information from SDOT:
Banner Image

The New Year brings a new off-ramp to Montlake

Jan. 6 brings a new SR 520 westbound off-ramp to East Lake Washington Boulevard; existing off-ramp in the Arboretum to close

New ramp configuration
Click image above for an animation of how traffic will operate when the new westbound SR 520 off-ramp opens to traffic.

Since September, crews have been constructing a new westbound SR 520 off-ramp to East Lake Washington Boulevard at the 24th Avenue East bridge crossing over SR 520. Crews plan to open the new off-ramp next week. Here’s what to expect:

  • Westbound SR 520 closure: From 11 p.m. Tuesday, Jan. 5, to 5 a.m. Wednesday, Jan. 6, crews will close all lanes and ramps of westbound SR 520 between 92nd Avenue Northeast and Montlake Boulevard to switch traffic onto the new off-ramp. At 5 a.m. Wednesday, Jan. 6, drivers will begin using the new westbound SR 520 off-ramp to East Lake Washington Boulevard.
  • Existing westbound SR 520 off-ramp to Lake Washington Boulevard East through the Arboretum to permanently close: This ramp will be closed during the traffic switch and removed later to accommodate the new West Approach Bridge North.
  • Temporary off-ramp configuration during construction: The new westbound SR 520 off-ramp to East Lake Washington Boulevard will open in a temporary configuration so we can provide a separate traffic lane on the 24th Avenue East overpass for construction vehicles to access the nearby construction staging area at the former Museum of History and Industry site.
  • Added stop signs to control traffic: Drivers exiting the new off-ramp must stop at two locations to reach East Lake Washington Boulevard. All drivers will be required to stop at 24th Avenue East to allow construction vehicles into a staging area and at a new 4-way stop at the East Lake Washington Boulevard intersection. Drivers can turn either left or right onto East Lake Washington Boulevard to reach their destination. As drivers adjust to the new off-ramp, WSDOT will work with the city of Seattle to monitor traffic conditions and adjust signal timing on Montlake Boulevard, as needed.
  • Bicycle-pedestrian access: For your safety, please continue to use the signed detour route along Montlake Boulevard. To avoid potential conflicts between bicyclists and pedestrians with construction vehicles and off-ramp drivers, the bicycle-pedestrian path across 24th Avenue East bridge will remain closed until the completion of the WABN project in 2017.  

Navigation changes on Lake Washington in coming months


For those hardy boaters still taking to the water over the winter, be advised of a temporary navigation change in effect on Lake Washington in early January. From Monday, Jan. 4 to Monday, Jan. 18, the west navigation channel under the SR 520 floating bridge will be closed. The east navigation channel will remain open, with a reduced navigational height of 58 feet. During this closure, crews will be installing a drilled shaft east of the temporary work bridge for the new West Approach Bridge North (WABN), a fixed structure which will connect the SR 520 floating bridge to Seattle’s Montlake neighborhood.


Crews on the WABN project expect to close the west navigation channel again in late January or early February 2016 to install the second drilled shaft east of the WABN temporary work bridge. Updates will be posted on the SR 520 Boater Information Web page.


An illustration of the west navigation channel closure is posted on our SR 520 Boater Information Web page.

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