HNTB serves as lead designer on new departure lanes that improve access amid rising travel volumes
SEATTLE (Sept. 19, 2025) – HNTB joins the Port of Seattle in highlighting a key milestone in the Roadway Improvements project aimed to alleviate the crowding and congestion along the departure and arrival drives at Seattle-Tacoma International Airport. The opening of the new Upper/Departures Drive, along with the completion of the westside retaining wall, is a highly visible step in the project evolution to travelers entering SEA Airport. As one of the fastest-growing airports in the U.S. for more than a decade, this milestone is just one part of SEA’s broader efforts to modernize its infrastructure, ensuring that the airport can meet the needs of more than 52 million travelers annually while maintaining a smooth, seamless experience for passengers.
Roadway improvements include two new southbound lanes, which serve as dedicated lanes for shuttles, taxis and airport parking access. These upgrades also feature expanded curbside access, signage improvements and advanced stormwater treatment systems to remove pollutants before they reach nearby streams. Behind the scenes, significant utility upgrades have been completed to support these improvements, providing long-term operational efficiency and sustainability. HNTB served as lead designer, working closely with the Port of Seattle throughout planning and execution.
This milestone also marks the transition to the next phase of improvements at SEA. With the new upper drive lanes now open, construction will shift to grading the area between the upper and lower drives. Once complete, traffic will be temporarily redirected to the middle section, creating space to raise the lower drive and finish that portion of the project. These carefully sequenced steps ensure passenger access remains smooth while long-term improvements to airport roadways continue to move forward.
In addition to this project, HNTB has partnered with the Port on several other key initiatives, including a new baggage-level TSA checkpoint to ease congestion, reconfiguration of the cell phone lot for better access and airfield work such as loading bridge replacements and pavement and utility upgrades.
“Our long-standing collaboration with the Port of Seattle reflects a shared commitment to enhancing the travel experience while positively impacting the surrounding community,” said Kris Agers, Washington office leader and senior vice president at HNTB. “The infrastructure upgrades designed by HNTB will improve travel efficiency and enhance the airport’s connection to the region it serves.”
CJ Grove, project manager at HNTB, added, “The new departure lanes are a critical step toward easing congestion and increasing efficiency. These enhancements address current needs as the region prepares to host the 2026 FIFA World Cup and are designed to integrate with potential future roadway improvements.”
“The new upper/departures drive marks a pivotal step toward modernizing how people access SEA,” said Heather Bornhorst, capital program leader at the Port of Seattle. “These enhancements are crucial in helping us meet growing demand while advancing the Port of Seattle Commission’s ground transportation goals to reduce congestion and improve ease of access and the customer experience.”
For more information on past and upcoming SEA improvements, visit the Port of Seattle’s Airport Capital Projects website.