Tunnels are a vital component of the nation's transportation network, and among the most challenging and complex infrastructure projects to design and deliver.
Industry leadership from HNTB's experts
Managing the Challenges of Major Transit Projects in Congested Urban Environments
As suburban sprawl reverses and urban population surges, most major transit projects are being squeezed into smaller, more complex, multilayered environments.
Trusted Innovative Underground Solutions
HNTB experts have the insight and knowledge to provide innovative solutions on a wide range of tunnels, including cut-and-cover, tunnel boring machine (TBM) tunnels, conventional tunneling, NATM, immersed tube tunnels, shaft construction and micro-tunneling. Learn more about the firm's award-winning projects on some of the country’s most complex tunneling projects.
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HNTB's projects and experts in the news
ENR Announces 2019 Global Best Projects Winners - ENR
The Alaskan Way Viaduct Replacement Program and State Route 99 Tunnel earn an Award of Merit honor
HNTB, Clients and Partners Celebrate Projects Recognized at ACEC Engineering Excellence Awards Gala - Informed Infrastructure
The Alaskan Way Viaduct Replacement Program in Seattle won the prestigious 2019 Grand Conceptor Award for the year’s best overall engineering accomplishment. HNTB served as engineer-of-record and lead tunnel designer.
SR 99 Tunnel Now Open to Traffic - Tunnel Business Magazine
WSDOT's innovative tunnel, part of one of the largest infrastructure projects in the country, opened to travelers in 2019
Digging Deep to Unlock the Waterfront: Massive New Tunnel Opens Below Downtown Seattle - Informed Infrastructure
The Washington State Department of Transportation (WSDOT) needed to replace the Alaskan Way Viaduct that carried a section of State Route 99 (SR 99) along the downtown waterfront. Ultimately, city and state officials decided to build a massive, deep-bored tunnel - read more on the SR 99 Tunnel.
Relevant articles on a variety of infrastructure topics
HNTB-Designed SR 99 Tunnel Opens in Downtown Seattle - Designer
On Feb. 4, 2019, the Washington State Department of Transportation officially opened the SR 99 tunnel — designed by HNTB — to drivers. The project was part of the Alaskan Way Viaduct Replacement program, one of the largest infrastructure projects in the United States.