California Builds $400M Rock Shed on Highway 140

The 675-foot concrete structure will protect the Yosemite-bound route from rockfall at a slide zone that has stayed active since 2006.

Updated on Nov. 9, 2026 in Construction

Long pale concrete rock shed curving along a steep granite mountainside above a winding mountain highway, with a crane frame at the far end. — Caltrans is building a $400 million, 675-foot concrete rock shed over Highway 140 near Yosemite to protect the route from a slide zone active since 2006. AI Illustration. Upload story photo >

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California is constructing the Ferguson Rock Shed, a $400 million, 675-foot concrete structure over Highway 140 near Yosemite. Highway 140 remains open on temporary bridges while the work proceeds.

Why it matters

The shed targets a mountainside that dumped close to 800,000 tons of rock onto the highway in 2006 and has remained active since. The project addresses a stretch of road that has been detoured for about 20 years.

The project carries an estimated $400 million price tag for a 675-foot shed with a 40-foot interior width, built in 11 precast concrete segments. The 2006 Ferguson Slide that prompted it dumped close to 800,000 tons of rock onto the highway, and completion is projected around 2030.

The players

California Department of Transportation

Caltrans is the state agency responsible for designing, building and maintaining California's state highway system, including Highway 140.

The details

Crews are assembling the shed from 11 precast concrete segments and pushing them into place around a curve over the original highway alignment. The segment-pushing method has not previously been used on a rock shed, and the first concrete pour was completed in July.

Spring 2006: The Ferguson Slide dumped rock onto the highway.
Summer 2025: Work on the rock shed began.
July: First concrete pour completed in the canyon.
Around 2030: Expected completion of the Ferguson Rock Shed.

Construction Landscape

The Ferguson Rock Shed follows the 2006 Ferguson Slide, which dumped close to 800,000 tons of rock onto Highway 140 and forced a detour lasting about 20 years. Its segment-pushing construction method has not previously been used on a rock shed, and California has only one comparable structure, on Highway 1 in Big Sur.

Drivers on Highway 140 continue to use temporary bridges while construction is underway, and the road remains open during the project. Once finished, the shed is meant to protect traffic from rockfall on a route that leads into Yosemite.

The takeaway

Large rock sheds can keep a major park route open where a slide zone remains unstable. The Ferguson project shows how a state can rebuild a critical corridor in place rather than abandon it.