Traffic Payout

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.