SR 524 - Locust & Larch Way - Intersection Improvements

Project News

  • Expect to see equipment in the area through May for utility work that needs to be done ahead of construction.
  • WSDOT plans to install two roundabouts to reduce congestion-related collisions on SR 524 (Filbert Road) at Larch Way and Locust Way.
  • This project is tentatively scheduled to begin in July 2018.

Why is WSDOT going to build roundabouts at the intersections of SR 524/Locust Way and SR 524/Larch Way?
These intersections, which are located on SR 524 (Filbert Road) where it passes under I-405, have a collision rate that is higher than the state average when compared to similar highways. 

Collision history
There were 81 collisions at these intersections from 2011 through 2015, approximately 16 each year. There were 36 injuries to drivers and passengers as the result of these collisions.

  • 47 rear-end collisions
  • 16 turning collisions
  • 11 fixed object collisions
  • 6 opposite direction collisions
  • 1 overturned vehicle

Roundabouts have a proven history of reducing collisions.
With approximately 16,000 trips on this stretch of SR 524 each day, improvements are necessary to reduce the number of collisions and keep traffic moving on Filbert Road. 

Intersection options studied
WSDOT considered six options for these intersections, but most required a wider highway to implement them. Widening will cost substantially more money than currently available because widening will need to address two creeks, a wetland, a narrow bridge built in 1935, right of way, and the I-405 bridge columns. Learn more about the options studied by WSDOT.

Congestion relief will require a separately-funded project
The roundabouts are a safety project designed to reduce the risk of collisions through these intersections.

There may be a slight improvement in through-traffic because cars will no longer need to block traffic while stopping to make a left turn.

Widening this section of SR 524 was included on the Regional Transportation Investment District list of projects for funding on the 2007 Proposition 1 ballot measure. Since voters defeated the measure, no funding has been identified to complete the widening of SR 524. A congestion-relief project will require widening the road, which is a more substantial project that we can accommodate with the current funding level. 


The End Result
Two roundabouts designed to operate in tandem to reduce the frequency and severity of collisions.

Project Benefits

  • Two new roundabouts that will reduce collisions on SR 524.
  • Roundabouts encourage traffic to keep moving at lower speeds, reducing the frequency and severity of collisions.
  • Drivers are less likely to be caught in a lengthy backup due to a crash.
  • Roundabouts are less expensive to build and maintain compared to traffic signals.


What is the project timeline?

  • October 18, 2016: Open house held at Lynnwood High School.
  • January 2018 - Project is scheduled to be advertised for competitive bidding
  • Summer 2018 - Construction occurs
  • Fall 2018 - Construction is operationally complete.

Financial Information

Financial Data for PIN 152411B
Funding Source Amount ($ in thousands)
2003 Gas Tax (Nickel Funding) $0
2005 Gas Tax (TPA) $0
Pre-Existing Funds (PEF) $4,402
CWA $0
Total $4,402


How can I get more information?

Frances Fedoriska 


A small map showing the location of Locust and Larch Ways on SR 524 near Lynnwood and Bothell, Washington.
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A small photo of the intersection of Larch Way and SR 524 near Bothell and Lynnwood.
The intersection of SR 524 (Filbert Road) and Larch Way.
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