As lead designer and engineer of record, HNTB helped a visionary P3 transform the gateway to the Golden Gate Bridge, including three tunnels and five viaduct bridges
SAN FRANCISCO (July 17, 2025) — HNTB congratulates the California Department of Transportation, the San Francisco County Transportation Authority and the Golden Link Concessionaire on the 10th anniversary of the award-winning Presidio Parkway — a visionary project that transformed the south access road to the Golden Gate Bridge, enhanced safety and mobility on U.S. 101, and reconnected the former Presidio military post to its iconic waterfront.
Presidio Parkway tunnels, completed in 2015
The Presidio Parkway replaced the structurally and seismically challenged Doyle Drive, a 1.6-mile corridor originally built in 1936. When the new Parkway opened to traffic on July 12, 2015, it marked the culmination of a multi-agency effort to deliver a transportation solution that honors both the natural and cultural landscape of the Presidio.
HNTB served as lead designer and engineer of record and provided construction design services for Phase II of the project. The firm’s scope of work included designing the project’s civil and utility infrastructure, the northbound high viaduct, five low viaduct bridges with on- and off-ramps, temporary detour structures and three cut-and-cover tunnels engineered to withstand a magnitude 8.3 earthquake — the maximum considered for the region, including liquefaction and tsunami risk given the proximity to the waterfront.
“The Presidio Parkway stands as a shining example of what visionary transportation agencies and citizens can accomplish when they come together in pursuit of a common goal,” said Katie Magee, HNTB lead designer and deputy project manager. “It’s more than a road — it’s a lasting legacy that continues to elevate safety, mobility and quality of life for San Franciscans and visitors alike.”
A legacy of innovation
When the 1989 Loma Prieta earthquake struck, it exposed the urgent seismic vulnerabilities of Doyle Drive. At the same time, the Presidio was transitioning from an active U.S. Army post to becoming part of the Golden Gate National Recreation Area — adding complexity and significance to the corridor’s transformation.
Caltrans and the SFCTA led a 14-year planning and delivery effort, culminating in a two-phased project.
“The Presidio Parkway was a complex, multilayered effort — from its context-sensitive design and stringent environmental requirements to its multi-agency coordination and innovative use of public-private partnerships to deliver the project years sooner than otherwise possible,” Magee said. “It leaves a powerful legacy for the industry. The project helped prove that major highways can accommodate strategic, targeted closures to accelerate construction, and it helped pioneer the use of deep-soil mixing — a groundbreaking technique in U.S. transportation infrastructure at the time.”
Infrastructure in harmony
Construction on one of the Presidio Parkway tunnels, completed 10 years ago
Another defining element of the Presidio Parkway is its ability to strike a balance between mobility and environmental and community stewardship. By concealing portions of the roadway within tunnels and shaping the structures to follow the area’s natural contours, the project restored sightlines of the bay and reconnected the Presidio to Crissy Field and the waterfront — areas previously cut off by Doyle Drive.
“The Presidio Parkway has become a model for context-sensitive design and delivery,” Magee said. “It shows what’s possible when technical excellence and public value go hand in hand.”
Today, the tops of the tunnels support 14 acres of landscaped green space, part of the country’s first and only urban national park. Featuring walking trails, overlooks, a visitors center and a popular playground, the Presidio Tunnel Tops have become a popular outdoor destination.
“The Tunnel Tops are the frosting on the project,” said Todd Hoekstra, former HNTB project manager. “A finishing touch that brings joy and beauty to all who visit.”
“It’s inspiring to witness how the area has been transformed, blending world-class engineering with inviting public space,” said Sarah Hersom, HNTB Northern California director of engineering. “This achievement will be cherished for generations to come.”