Construction crews in Washington state have been making steady progress on the North Spokane Corridor (NSC), a 10.5-mile freeway originally conceived in 1946. Estimated to cost a total $1.5 billion, the mega project aims to improve mobility by allowing motorists and freight to move north and south through metropolitan Spokane.

At present, there are only two north-south trade routes through Spokane, including U.S. 395, which carries over 7 million tons of freight through the city each year. Once the NSC is complete, it will connect I-90 on the south end to existing U.S. 2 (at Farwell Road) and U.S. 395 (at Wandermere) on the north end.

“This project will accomplish quite a bit for the region,” says Mike Gribner, Regional Administrator for the Washington Department of Transportation (WSDOT). “Currently, all freight and commuter traffic has to travel through signalized city streets and neighborhoods. This causes congestion issues and safety concerns and adds to commute times. The North Spokane Corridor is designed to move traffic off city streets and onto a regional system, which prevents a lot of wear and tear on city infrastructure.” 

Additionally, the new 60-mile-per-hour corridor will feature the Children of the Sun pedestrian/bicycle trail along its full length and support future alternative transportation options including park-and-ride lots, vanpooling operations and high-capacity transit.

This multimodal development led by WSDOT has been completed in pieces as funding has allowed. Connecting Washington, a $16 billion transportation investment package passed by the state Legislature in 2015, allocated $879 million to the NSC. Thanks to this additional infusion of capital, all remaining portions of the NSC are now fully funded.

A Complex Puzzle

This project has been likened to a complex jigsaw puzzle, requiring painstaking consideration and patience to fit all the pieces together just right. Behind-the-scenes activities such as environmental studies, right-of-way acquisitions and public hearings have been ongoing for decades, but the necessary framework for the NSC was not available until April 1997, when the Final Environmental Impact Statement (FEIS) was approved.

Only the northern half of the NSC has taken visible shape in the last 20 years. However, despite many logistical challenges and other twists, the game is ramping up with the final series of NSC construction projects now fully funded. With all the critical pieces finally in place, the entire puzzle is set to be finished by 2029.

According to WSDOT’s latest traffic projections, there will be approximately 70,000 daily trips on the corridor after it initially opens. While the new regional facility will be a viable option for commuters, it is part of a larger economic engine designed for the state to move freight. “We’re caught up in the national trend of e-commerce, which is probably one of the biggest drivers of freight transportation across this region,” Gribner says. 

Key Pieces of the High-Speed Corridor Project

This high-speed corridor project first broke ground in August 2001 with grading work between Hawthorne Road and Farwell Road. Since then several miles of freeway, three interchanges, 30 bridges, one railroad tunnel and a portion of the Children of the Sun Trail that parallels the NSC have been built.

A major milestone was reached in October 2012 when the 5.7-mile northern half of the NSC – from Francis Avenue to U.S. 395 – turned operational. Construction on the southern half of the project has been underway ever since, kicking off with the yearlong replacement of the Francis Avenue bridge over the Burlington Northern Santa Fe (BNSF) railroad and future NSC. Other significant areas of progress include: completion of phase one of the BNSF railroad realignment in 2015; construction of a new roundabout at the Wellesley/Freya intersection in 2016; and cleanup of contaminated ground in 2017 at a site where acetylene gas was once produced. Another grading project kicked off in 2018 along with construction of new bridges over Freya Street. The Columbia Avenue to Freya Street paving project, which will complete the interchange at Freya, continues this year.

The NSC staging plan for the next four years includes: phase two of the BNSF railroad realignment; building the remaining portion of the Children of the Sun Trail and pedestrian bridges and related amenities; creating a new interchange at Wellesley Avenue; and new roadway/bridge construction along the NSC between Columbia Avenue and Sprague Avenue.

Currently, one of the biggest construction hurdles is finding the right-sized projects to match funding allocations for each biennium, says WSDOT Assistant Project Engineer Terrence Lynch, PE. Right-of-way acquisitions, especially those involving larger industrial or commercial properties, have also been challenging.

“Another complexity is connecting the North Spokane Corridor to an area of I-90 that is one of the most congested through the Spokane region. We had to get pretty creative with our design to prove to the Federal Highway Administration that the new corridor will not adversely impact operations and safety on I-90,” Lynch adds. “Part of our design includes braided ramps to eliminate weaving movements as traffic enters and exits the interstate. We also had to stretch out the interchange to maintain as many access points to and from I-90 as there are today.”

Oil Contamination Nearly Derails Alignment Plans

Through the FEIS process, the BNSF corridor was selected as the preferred location for the NSC in part because the existing corridor minimized impacts to developed properties. The second phase of the BNSF railroad realignment, which began this past September and will cost just over $26 million, represents the first large funding expenditure allocated by the Connecting Washington package. 

This contract was awarded to Spokane-based Halme Construction, Inc. The scope of work consists of grading activities, removal of an existing railroad bridge, and relocation and realignment of the railroad track to make way for the NSC mainline alignment section between Rowan Avenue and Cleveland Avenue. The new railway alignment will cross over Wellesley Avenue, a major east-west arterial, via two newly constructed railroad bridges. This complex undertaking necessitates the closure of Wellesley, from Market Street to Freya Street, for three years.

This leg of the project is critical to the overall NSC construction schedule. “There are two other projects that are going to be right on the heels of this rail realignment. Until the rail realignment is about halfway complete, we can’t begin those other projects,” Lynch says.

Approximately 400,000 cubic yards of material – which will be repurposed to build the NSC roadway – must be excavated in order to relocate the railroad. Also, to continue rail operations while the main track is being built, workers are constructing a 1.5-mile-long shoofly, or detour, about 150 feet east of the existing tracks. “Since the railroad has to remain in commission, we only have enough free area to embank about half of the excavated material right now,” Lynch says. As a result, crews will have to temporarily stockpile the excess material until the permanent track gets realigned and the shoofly is removed.

Underground oil contamination at a former locomotive refueling yard is another factor impacting realignment work. Initially, BNSF believed the contamination was confined to the upper layers of soil at a site dubbed “Black Tank,” which is situated above the Spokane Valley-Rathdrum Prairie Aquifer. However, in 2008, the state Department of Ecology determined that a plume of thick oil sits roughly 170 feet beneath the surface, impacting some 7 acres of the sole source aquifer. BNSF and Marathon Oil are legally responsible for what will be a challenging cleanup.

Because the NSC project’s Connecting Washington funds have to be spent within a certain time frame, the railroad realignment cannot be halted until remediation is completed, which could take up to 20 years. The state considered an elevated freeway redesign option; however, citizens in the nearby Hillyard neighborhood opposed this idea because a possible 35-foot-tall elevated freeway structure might negatively affect the historic business district’s aesthetics. In addition, a freeway redesign could potentially impact plans for a trail and park in the area.

To resolve these concerns and prevent the NSC project from being shut down, an agreement was reached by WSDOT, BNSF, and the state Department of Ecology that allows the NSC to proceed over the Black Tank site and near its original alignment while ensuring the site is thoroughly cleaned up in a reasonable, realistic time frame. 

Practical Solutions Save Millions

Another highlight of the NSC project is WSDOT’s practical design approach, which is part of the agency’s practical solutions initiative. This approach aims to reduce costs and provide interim drivable links as portions of the freeway are completed. 

“As we become more intimate with the design and understand the risks related to fulfilling this project, we can identify things that are unnecessary and remove them from the project plans,” Gribner explains. 

For example, several opportunities for cost savings emerged in the section between I-90 and Freya Street prior to construction. The practical design work resulted in modifications to the NSC’s elevation, alignment and width along with changes to the alignment of the relocated BNSF corridor and the NSC/I-90 connection. These combined changes saved $850 million in construction costs while maintaining operational functionality and allowing for staged construction.

Ultimately, the practical design approach has cut the NSC’s total project costs by about half. “WSDOT’s practical solutions philosophy is ‘right project, right time, right place’ – and recognizing that we live in a fiscally constrained world. Any of the savings that we can generate on projects like this – and still have an appropriate project – we can use to solve a problem somewhere else,” Gribner says.

A Heart for Community

Ultimately, over 600 existing properties (a combination of homes and businesses) have to be removed to clear the way for construction. But along the chosen alignment there are approximately 2,100 acres of land zoned for commercial or industrial development, which provides economic growth opportunities. Such development would be a boon to the region’s vitality, including for those living in poorer or declining neighborhoods.

With struggling community members in mind, WSDOT is in discussions with various organizations to determine whether low-cost housing can be placed in certain right-of-way areas of the project. “One of the places we’re considering is a unique piece of land where the corridor crosses the Spokane River,” Gribner says. “We are talking to folks about putting in transitional housing so people who are getting back on their feet have a place to stay while they transition back into society. The other thing we’ve contemplated is generating maintenance revenue for placemaking areas so the city isn’t burdened with taxes required for upkeep.”

These placemaking areas are part of a public engagement initiative to ensure citizens are included in the planning, design and management of public spaces along the corridor. WSDOT has teamed up with Eastern Washington University’s Urban and Regional Planning program, the city of Spokane, the Spokane Transit Authority and the local school district to collaborate with community members and identify placemaking opportunities. 

A series of open-house “charettes” are being hosted year-round to connect with the public and figure out ways the project can tie into the community. “These charettes provide a forum for ideas and offer the unique advantage of immediate feedback. More importantly, it allows participants to be a mutual author of the plan, and provides a sense of ownership,” Lynch says. 

Places where certain ideas have already been implemented include retaining walls imprinted with a ‘hiking heron’ (a heron wearing boots) and a bridge with visual representations of the region’s railroad history cast into the concrete columns. A variety of other placemaking concepts are being considered, including plazas and dog parks adjacent to the Children of the Sun Trail, lighting on the trail to enhance safety, and an amphitheater under an elevated section of freeway.

For a community continuing to grow and expand, these efforts to make the North Spokane Corridor safer and more inviting are certainly appreciated by many. Inevitably, this unique development process will be remembered for generations to come.