Stabilized Section of Highway 1 Reopens in Northern California Two Months Early

Highway 1 in Northern California — Photo courtesy of Caltrans

An aerial view shows slope stabilization work along a landslide-prone stretch of California’s Highway 1 near Big Sur, where earthwork and drainage improvements helped reopen the coastal route two months ahead of schedule.

Just one week after early January heavy rains caused new rockfall six miles south of Regent’s Slide—temporarily closing access to the area on California’s Highway 1 that was under repair since Feb. 9, 2024—the California Dept. of Transportation's District 5 announced Jan. 14 that the highway was reopened. The work on the road that leads to Big Sur completed more than two months ahead of schedule.

Caltrans had previously stated that it expected the 6.9-mile stretch to reopen in late March, at the earliest.

In the days after the recent rainfall, Caltrans' geotech team removed large rocks and boulders from the newly repaved roadway, returning access and allowing workers to make the final touches.

The reopening brings much relief to businesses in Big Sur where access had been severely limited. An adjacent slide had closed a significant stretch of the highway for three years.

“We will continue to monitor slope movement at Regent’s Slide through surface-mounted prisms and a series of sub-surface shape arrays,” sats Kevin Drabinski, a Caltrans District 5 spokesman. “One of the successes of the repairs is that the slope above the roadway is stable and can be verified by our measuring equipment.”

Stability of the slope had been so tenuous over the course of the repair work that two-remote controlled bulldozers and two remote-controlled excavators were used to increase productivity while protecting workers from the slide area’s instability.

Protective netting covering the lower third of the Regent’s Slide repairs, keeping rocks and debris from falling onto the roadway, is intended to be permanent. Similar netting is in place at dozens of other locations on the Big Sur coast. “During two recent rain events, the netting has performed as expected," says Drabinski.

Over the course of the repair work, crews installed more than 4,600 shear dowels – 60-ft-long steel bars that were drilled and cemented into place in the upper two-thirds of the slope. “These are helping to stabilize the slope in the near and long term,” says Drabinski.

Caltrans has estimated the cost of repairs at $82 million.