160th, Greenwood, and Innis Arden Intersection Project
Thank you for your interest in the 160th, Greenwood, and Innis Arden Intersection Project. We would appreciate your input on construction phasing, tree replanting locations, and the inclusion of public art in the project area. If you were unable to attend the information session on September 25, please take a moment to review the information below before completing the survey.
This project will improve the intersection of Greenwood Avenue N with N 160th Street and NW Innis Arden Way by replacing the current stop signs with a roundabout.
We are currently in Phase 2 of this project: Design and construction. We are reviewing 60% design plans and specifications.
Project Background
Shoreline Community College built student housing on campus, completed in 2019. The College did a traffic study for the new housing. It showed that the City’s delay standards weren’t being met at the intersection of Greenwood Avenue N with N 160th Street and NW Innis Arden Way. The Shoreline Community College campus housing project triggered transportation impact mitigation.
The City and College collaborated on a mitigation agreement, which included studying a signalized intersection versus roundabout intersection including community feedback. A roundabout was selected as the preferred concept in November 2019 based on 7 criteria.
Other safety features in the project design include pedestrian activate flashing beacons at every crossing, street lighting improvements, filled gaps in sidewalks, and improved bike connections.
The project is primarily funded by the College.
Timeline
- Concept Design in 2019 finishing up in early 2020.
- Design kicked off early 2023
- 30% Design August 2023
- 60% Design March 2024
- 90% Design October/November 2024
- Advertisement – January 2025
- Construction – March through September 2025
- Substantial Completion by January 2026 required per agreement
Intersection Design
Click the map image for a larger pdf version
A 5-leg roundabout was chosen as the safest and most efficient solution to move increased traffic volume through the intersection. This design minimizes impacts to neighboring properties. Challenges in design for this project include existing utilities, the steeper grade of 160th Street, transit access, tree impacts, and providing safe pedestrian pathways.
Tree impacts and replacement
Click the image above for a larger pdf version
Tree protection has been and continues to be important to the project team. We project that we will need to remove 14 trees to complete the project. During our design work, we kept trees in mind and made changes such as minimizing grading, raising the intersection slightly, and removing a leg of the intersection in order to protect trees.
We are looking at multiple locations in the project area to replant trees. We are not yet sure how many we can place as we are still confirming final locations of utilities that could conflict with new plantings. The areas marked in red below are possible locations for replanting.
We would like your input on whether to prioritize planting trees in the center island of the roundabout or placing public art. We would also like to hear if you would prefer we keep the topmost sidewalk in the image or remove it in order to plant additional trees. These questions are in the survey below.
Construction Impacts
We expect construction activities to take approximately 6.5 months. Typical impacts include:
- Noise and equipment exhaust
- Dust – contractor to water down open soils
- Equipment and materials staging
- Temporary driveway shutdowns
- Temporary pedestrian pathways
- Traffic delays associated with long periods of flagging and single-lane access.
As we consider how to manage construction safety during this project, we would like to hear your input on construction phasing.
One option is minimize intersection shutdowns and detours. This option will take a longer time to complete and likely increase construction costs slightly. The alternative option would be to fully close the intersection so we can complete construction in a shorter period of time. We can also consider allowing night work, which could be noisy and disruptive to neighbors.
Please take the survey below to provide your input on the options that would be acceptable to you.
More information
To learn more about the project, visit the project page on the City's website at shorelinewa.gov/160intersection.
Questions? Contact Project Manager Zach Evans at zevans@shorelinewa.gov.
