Thursday, December 20, 2012

Kirkland area travelers, get ready to meet your new interchange

By guest blogger Anne Broache

After some 18 months of construction, we’ll soon be finished revamping the area where Northeast 116th Street meets Interstate 405. Our goals were to improve your access to and from the highway at this interchange, and to upgrade safety for drivers, bicyclists and pedestrians alike.

What’s new?
For drivers:
  • New lanes and traffic signals on Northeast 116th Street and 120th Avenue Northeast
  • A rebuilt bridge with additional lanes over the railroad
  • A new interchange design aimed at boosting traffic flow (more on that below)
  • More space for vehicles on the I-405/Northeast 116th Street on- and off-ramps, resulting in decreased merging and collision risks
For bicyclists and pedestrians:
  • Improved lighting
  • Wider sidewalks
  • A continuous bike lane through the interchange area
For the environment:
  • A new storm water pond and drainage vaults to preserve water quality
Drivers traveled through the new Single Point Urban Interchange
(SPUI) at NE 116th Street and I-405 in Kirkland on its first day of operation, Dec. 20.
This SPUI is the first interchange design
of its kind on the I-405 corridor.
Most notably, we transformed this interchange from a traditional one to a more efficient half Single Point Urban Interchange, or SPUI (pronounced “spooey”). This SPUI is designed to maximize traffic flow in this notoriously congested area for Kirkland commuters heading to and from I-405.
How does a SPUI work?
With the new SPUI design, the on- and off-ramps converge at a single location controlled by one set of traffic signals at the center of the interchange. The signal in this case is located on the underside of the I-405 overpass.
The SPUI design increases the number of vehicles that can clear the interchange each time the light turns green for a particular stream of traffic.
Want to learn more?
This video explores the interchange’s new features so you’ll know what to expect. You can also see more photos of the construction progress at our Flickr page.
Finally, we’d like to send a special thank you to all of the Kirkland commuters who experienced the construction closures and delays while we worked to improve this interchange.


Nick said...

Is the timing of the lights final yet? Right now you tend to get cars moving East stuck in the intersection.
Also why is there no arrow for cars turning RIGHT from Northbound 120th ave to Eastbound 116th? That would really help the flow there.

WSDOT said...

Hi Nick, thanks for your questions and comments. After we analyze new traffic numbers, we may adjust the signal timing as necessary to accommodate various traffic volumes. We’ll pass your comment on to WSDOT’s signal operations section.
Our traffic engineers decided against a right-turn arrow on northbound 120th Avenue NE at NE 116th Street because that particular signal phase is needed for pedestrians to safely cross the southbound on-ramp to I-405.

Adeline Crinks said...

The new 116th intersection is great for people using 405, etc. but unfortunately, for the residents who live on 116th, one morning last week the decibel level of traffic noise outisde my bedroom window was 91 decibels!!! Who is responsible for providing protection for residents when the traffic noise reaches that level?
Adeline Crinks

WSDOT said...

Hi Adeline, we'd be happy to look into this issue for you. To protect your privacy, could you send an email detailing your concerns (including your location) to Steve Peer, our public information officer? His address is Thanks again for reaching out to us.

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