Northgate Pedestrian and Bicycle Bridge

Updated: April 9, 2021

What’s happening now?

Successful bridge span deliveries and upcoming span installation

We are pleased to share that both bridge spans were successfully delivered in February and in March. The next major milestone will be the installation of these spans across I-5. During this work, we'll erect 2 bridge spans; each will be assembled in the median of I-5, moved into place using self-propelled transporters, and lifted by cranes.

Bridge spans being delivered.
Bridge segment being offloaded

The time lapse video below automatically updates on a regular basis with the latest images from the construction site.

Bridge span installations over I-5 taking place in May

The next major milestone will be the bridge span installations across I-5. During this work, we'll erect 2 bridge spans; each will be assembled in the median of I-5, moved into place using self-propelled transporters (essentially, mini remote-controlled cars), and lifted by cranes. See detour information below.

Work will take place overnight over two weekends in May.

May 8 and 9: Crews will begin setup as early as 9 PM. Northbound I-5 lanes will close at 11:59 PM on Saturday, May 8, and will reopen at 4:30 AM on Sunday, May 9. Traffic will be detoured onto Lake City Way NE.

Northbound detour map.
Bridge segment being offloaded

May 15 and 16: Crews will begin setup as early as 9 PM. Southbound I-5 lanes will close at 11:59 PM on Saturday, May 15, and will reopen at 4:30 AM on Sunday, May 16. Traffic will be detoured onto SR-99.

Southbound detour map.
Bridge segment being offloaded

FAQ
Q: Why do you need a full closure of I-5 in both directions?
A: During the closure, the new bridge spans need to be moved into place using self-propelled transporters (essentially, mini remote-controlled cars) and lifted with cranes. To safely complete this work, a full closure is needed to ensure enough space is available for crew members, large machinery, and equipment staging.

Q: What material will be used for the spans?
A: The bridge spans are made of steel, a common and proven material for hundreds of thousands of bridges across the nation. All bridge materials go through rigorous quality assurance testing during fabrication, assembly, and installation, including the spans across I-5.

Q: How can I prepare for the closures?
A: During the installation of the bridge spans over I-5, it's important to plan ahead and allow for extra travel time. For your safety and that of others, it's critical to keep your eyes on the road while work is taking place, and to pay careful attention to site signage, traffic alerts, and email updates leading up to the weekend closures.

Q: Will there be more full closures of I-5 in the future?
A: If work is not completed by May 16, a third weekend closure will be put in place on May 22 and 23. Updates will be provided in advance of this closure, if applicable. Once the bridge span installation over I-5 is complete, we don't anticipate additional full freeway closures.

East side of I-5: 1st Ave NE (between NE 92nd St and NE 107th St)

Pouring concrete for bridge spans and bridge approach
Deck work
Removing temporary support structures
Electrical work
Sidewall support work
Installing steel reinforcements and pouring concrete structures for bridge support

West side of I-5 (north side of North Seattle College and along N 100th St)

Paving work for landing trail
Installation of steel reinforcements for bride support structures
Installation of electrical units
Pouring concrete for curb ramps
Pouring concrete for bridge approach

I-5 median (near the I-5 northbound express lane at NE 103rd St)

Nighttime testing of materials
Installation of bridge span decking
Touchup painting of bridge spans
Installation of throw barrier
Installation of support posts
Bridge span welding work

Our commitment to be a good neighbor

We will keep you informed and minimize our impacts. During construction, we're committed to working closely with project neighbors and will:

Be available for questions
Provide advance notice about construction through email updates and other promotions
Work closely with North Seattle College to communicate major milestones to students, faculty, and staff
Ensure project signage is clear and effective to encourage safety and caution near active work zones
Maintain access to businesses

What to expect during construction

Dust, noise, and construction vehicle activity, including cranes
Some nighttime and weekend work
Detours for people walking and biking
Traffic lane restrictions and closures
Construction staging and parking impacts near the construction sites, including on the North Seattle College campus on the west side and NE 100th St (at 1st Ave NE) on the east side
Closure of the North Seattle Park & Ride on 1st Ave NE

Long-term closure of North Seattle Park & Ride

The North Seattle Park and Ride (10001 1st Ave NE) will now be closed until fall 2021 for construction of the Northgate Ped/Bike Bridge project. The Seattle Department of Transportation is partnering with the Washington State Department of Transportation and King County Metro during the construction of the bridge. The lot will be used to stage equipment and materials for the duration of the closure. For more details, including alternative parking areas, view the full notice here.

Questions? Contact the project team at NorthgateBridge@seattle.gov

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Project overview

The Northgate neighborhood is a major residential and employment destination that continues to grow. With the completion of Sound Transit’s Link light rail station in 2021, the neighborhood is poised to become one of the region’s most active transit hubs. Today, a 10-lane interstate divides the neighborhood, and to walk between North Seattle College and the existing transit center is 25 minutes or more.

Connecting communities on the east and west sides of I-5 in Northgate

We designed a new, accessible, all ages and abilities pedestrian and bike bridge over Interstate 5 (I-5) in Northgate. The Northgate Ped/Bike Bridge will improve access to communities, services, and opportunities on the east and west sides of I-5 in Northgate and Licton Springs, helping knit together a historically divided area. It’ll also reduce travel time for people walking and biking between the east and west sides of I-5. When complete, the bridge will help connect the neighborhood’s thriving job and retail centers with the rest of the city and region.

The new bridge will span roughly 1,900 feet over I-5, landing at North Seattle College on the west side and at 1st Ave NE and NE 100th St, near the future light rail station, on the east side.

The project consists of four main parts:

Bridge spans over I-5
Western approach between North Seattle College and wetland area, connecting to College Way N and N 100th St
Eastern approach between I-5 and 1st Ave NE at NE 100th St, near the King County Transit Center
Multi-use path along 1st Ave NE

The project will benefit the area by providing:

A new connection over I-5, decreasing travel times for people walking and biking between the 2 sides of the highway
Safety improvements and access for people walking and biking throughout the Northgate area
Better access to regional transit at the King County Transit Center and future Link light rail station, resulting in increased use of transit facilities
Improved connections between the Northgate retail center for its employees and customers and for residents and visitors to other nearby amenities, such as parks and medical and social services

Project location

Design renderings

The view from I-5 traveling north.
Bridge view from road

The user experience walking or biking across the bridge.
Truss Passage

A view of the bridge, looking east.
Campus Pond Overlook

1st Ave NE street improvements

1st Ave NE features

Upon project completion, 1st Ave NE will be restored and include a new 2-way protected bike lane (PBL), between 92nd and 103rd along the west side of the street (see image below).

At NE 103rd St, people biking will use the crosswalk to accessthe east side of the street, where a multi-use path or widened sidewalk will continue north to Northgate Way.

1st Ave NE will have one vehicle travel lane in each direction with a left‑turn pocket at 100th St. The existing transit center bus stops will be relocated to the east side of 1st Ave NE, between NE 100th and NE 103rd streets. King County Metro plans to restore transit stops on 1st in 2021.

North Seattle's growing bike network

Once complete, the PBL will connect with the new Northgate Bridge at NE 100th St, the existing bike lanes on 92nd, and other community connections in the area. These improvements will provide easy access to regional transit and to the citywide network of walking and biking routes.

Protected bike lanes combine the elements of a multi-use pathwith a conventional bike lane. They provide space for bikes that is separated from vehicles, parking lanes, and sidewalks.

1st ave ne protected bike lane and multi-use path

Recent cost-saving changes

We formed a new design team in 2016 to help reduce project costs and meet project goals. The team developed a bridge design that includes the following cost-saving changes and design improvements:

Original design (prior to 2017)	Revised design (2017 to present)
20-foot-wide walkway on bridge	16-foot-wide walkway on bridge
2,100-foot-long bridge length	Shortened bridge length to 1,900 feet
East approach conflicted with WSDOT Park-and-Ride at 1st Ave NE	East approach modified as it touches down near 1st Ave NE, simplifying the connection and preserving the WSDOT Park-and-Ride lot
West approach included stairs at the North Seattle College, with limited sight distance	West approach modified to improve sight distances and make a more direct connection
Complicated construction approach	Standard construction approach to reduce project duration
Tube/truss design (enclosed)	More open structure and more graceful bridge transition

Finally, an added benefit of the revised design is enhanced user experience with features such as a wetland wildlife overlook and a view of arriving light rail trains at NE 100th St.

What we’ve heard through design

Based on community input throughout the project, we know there’s interest in:

Minimizing environmental impacts of the bridge by making sure, for example, that the project doesn’t disturb wildlife during construction and ensuring the bridge’s drainage system (for stormwater) is designed to enhance wetlands on the west end
Ensuring safety and security of all bridge travelers
Wayfinding and traffic control
The experience of people biking and using other wheeled devices (e.g., scooters, wheelchairs, strollers, rollerblades, suitcases, etc.)
Connecting the bridge to other infrastructure, including neighborhood bike routes
Separating or managing modes of traffic on the bridge

Other topics of interest included the project’s cost, the bridge’s durability, and maintaining vegetation.

We value the community input provided to date and thank you all for your continued interest.

Tree mitigation plan

Throughout our preconstruction outreach, the project team heard from many people asking about our tree mitigation plan. We will be removing 93 trees during this project, and we will be planting 464. The map below shows the full details. You can click on the map to download a PDF of the plan.

Designing for a safer bridge

During each phase (planning, design, and pre-construction) of public outreach, we heard that bridge safety is a priority for all bridge users. The sections below outline how safety is incorporated into all aspects of the bridge's design.

Design and accessibility

Throughout the design process, we used an approach called Crime Prevention Through Environmental Design (CPTED). This approach is based on the idea that people's behavior within an urban environment is influenced by the design of that environment.

CPTED strategies include things like providing ample lighting to avoid blind spots, maximizing sight distance and visibility (sometimes called "passive surveillance"), and using materials that promote easy maintenance. This strategy also aims to create spaces that give a sense of ownership of public space and a sense of shared responsibility for personal security.

There are several safety elements on the bridge, including:

Minimal surface area for vandalism
Overhead pedestrian lighting
Emergency call boxes
Pedestrian guardrails
Lighting on handrails
Throw fences

The City of Seattle strives to make city programs, services, and activities equally accessible to all. Our bridge design complies with 2010 ADA Standards and includes the following features:

A bridge slope of 4.3%, except between the Sound Transit mezzanine and the NE 100th St level, which is 8.1%. This section has ADA-compliant handrail grips and 1.8%-slope landings every 30 feet to provide resting places.
Elevator access via the Northgate Station Garage, including where the bridge connects to the Northgate Link light rail station, during normal hours of operation.
Curb ramps along 1st Ave NE and NE 100th St, where the bridge spur lands.
Accessible pedestrian signals at the intersection of 1st Ave NE and NE 100th St, which will offer push-button activation, audible signals, and vibrations to indicate when it's safe to cross the street.

Bridge safety elements

Materials

All bridge materials and connections will go through intensive testing during construction, including the spans across I-5, which will undergo rigorous quality assurance testing during fabrication, assembly, and installation. The trusses of our bridge will be made of steel, a common and proven material and design for hundreds of bridges across the nation.

Life expectancy

Our bridge was required to meet the 75-year design life expectancy criteria consistent with the American Association of State Highway and Transportation Officials (AASHTO) design codes. Not only does our design meet this standard, it's expected to exceed a lifespan of more than 100 years with routine maintenance during its service life.

Environmental

We selected vegetation and greenery around the bridge with safety in mind. Creating park-like qualities on the trails and spaces near the bridge will provide a comfortable and enjoyable atmosphere and a "sense of place" for all users. Examples of this can be seen on the west side with a wildlife overlook, and on the east side where we're proposing a "gallery forest," or screen of tall and narrow trees between the bridge and the freeway, providing relief from views of the freeway and filtering air quality.

Additional environmental features include:

Planting low-growing shrubs and bushes around the bridge
Trimming, thinning, or removing existing trees and undergrowth to create open sight lines
Carefully designed plantings on the west side of the bridge so that pedestrians on the landing will have a clearer view of North Seattle College (NSC), and those on the NSC playing field and in the parking lot will see bridge users approaching

Schedule

We expect construction to begin early 2020, and to be complete in fall 2021, prior to the opening of the Link light rail station in September 2021.

Project Schedule

Funding

We’ve secured funding from various sources in addition to the voter-approved Move Seattle levy. These include SDOT, Sound Transit, Washington State, and additional local funds.

Stay informed

Email is the best way to stay up to date on the project during the entire construction process.

Click here to sign up to receive project email updates

Park and Ride Information

Click this link for more details about which Park and Rides are open and available throughout construction.

Outreach events

Date	Events

January 9, 2020	Construction drop-in session at Olympic View Elementary
January 8, 2020	Construction drop-in session at Aljoya Thornton Place
January 7, 2020	Construction drop-in session at North Seattle College
September 28, 2019	Live in D5
September 25, 2019	North Seattle College Fall Fest
September 3, 2019	Olympic View Ice Cream Social
July 17, 2019	Maple Leaf Summer Social
July 13, 2019	Live in D5
April 24, 2019	North Seattle College Fair
October 24, 2018	Maple Leaf Community Council
July 19, 2018	Thornton Creek Alliance
July 18, 2018	Maple Leaf Summer Social
June 30, 2018	Live in D5!
May 11, 2018	North Seattle College Board of Trustees meeting
April 18, 2018	North Seattle College Earth Fair
April 18, 2018	North Seattle College Earth Fair
March 21, 2018	Drop-in session at Neighborcare Health at Meridian
March 20, 2018	Drop-in session at Aljoya Thornton Place
March 19, 2018	Drop-in session at North Seattle College
February 8, 2018	Sierra Club
November 28, 2017	North Seattle College campus meeting
November 2, 2017	Haller Lake Community Club
August 13, 2017	Idriss Mosque BBQ
August 9, 2017	Seattle Pedestrian Advisory Board Walking Tour
August 3, 2017	Public open house
July 26, 2017	Maple Leaf Summer Social
July 22, 2017	Live in D5!
June 30, 2017	Department of Neighborhoods Community Conversation Meridian Manor
June 14, 2017	Maple Leaf Community Council
June 14, 2017	Seattle Pedestrian Advisory Board
June 7, 2017	Seattle Bicycle Advisory Board
May 18, 2017	Seattle Design Commission
May 6	King County Metro Transit Oriented Development public meeting
April 29, 2017	Housing Affordability and Livability community open house (sponsored by Dept. of Neighborhoods)
June 22, 2016	North District Council
May 25, 2016	Feet First
May 18, 2016	Licton Springs Community Council
May 17, 2016	Victory Heights Community Council
May 16, 2016	North Seattle College (Campus meeting)
May 5, 2016	North Seattle College (students)
October 15, 2015	Public open house
September 17, 2015	Seattle Design Commission briefing
August 18, 2015	Seattle Design Commission subcommittee meeting
July 29, 2015	Maple Leaf Summer Social
July 15, 2015	North Seattle Chamber of Commerce
June 17, 2015	Licton Springs Community Council
June 17, 2015	Seattle Pedestrian Advisory Board
June 24, 2015	Pinehurst Community Council
May 27, 2015	Northwest District Council Briefing
May 26, 2015	Cascade Bicycle Club: Connect Northgate
May 22, 2015	Seattle Neighborhood Expo
May 12, 2015	Meadowbrook Community Council
May 2015	Seattle Pedestrian Advisory Board
April 29, 2015	Maple Leaf Community Council
April 22, 2015	North Seattle College Earth Day Symposium
October 21, 2014	North Seattle College
September 10, 2014	Public briefing
June 3, 2014	Open house
March 2014	Sound Transit open house
February 2014	Seattle Bicycle Advisory Board
February 2014	Seattle Pedestrian Advisory Board