When the team at Granite Construction took on a project to fix Regent's Slide that nearly wiped out State Route 1 — also known as the Pacific Coast Highway — near Big Sur, they knew it would be difficult.
The job was part construction, part mountaineering. The team members pressed ahead, not knowing they would have to use techniques they had only read about.
Granite Construction photo
Still, the Granite team wrapped up the difficult project in mid-January 2026, months ahead of schedule. The slide, caused by heavy rains in the Big Sur area, wrecked the road, the main route for residents to get life's necessities.
Granite worked closely with Caltrans and other contractors who specialized in stabilizing steep embankments. Granite also worked hand-in-hand with Caterpillar reps to provide remote-controlled equipment for this challenging project.
Even a casual observer could tell this was no ordinary job by the presence of a Boeing CH-47 Chinook heavy-lift helicopter. The helicopter was essential for ferrying equipment, gasoline, water and other essentials down the hillside from a fire road to the precarious perch where the workers and machines kept busy with their tasks. The Chinook brought up to 23,000 lbs. of equipment each trip down the hillside.
Regent's Slide closed about 7 mi. of S.R. 1 with a repair cost of $50.2 million.
Papich Construction, recently acquired by Granite, did the lion's share of the tasks. Workers removed approximately 1 million tons of dirt and rock on the hillside, securing it above the highway.
Keith O'Connor, Granite's project manager, worked with other Granite teams dealing with slides before taking on this precarious hillside. He told Construction Equipment Guide that he was confident in his team's ability to get the job done but put the highest priority on safety.
"We had never tackled a slide like this on such rugged terrain," he said. "But we made sure that everyone was going to get home safely after work. And we did that."
Granite Construction photo
Workers who clung to the hillside doing handwork were tethered with safety harnesses much like a roofer working up and down a steep roof. Even the bulldozers and excavators had heavy winches attached, in case the dirt began slipping out from under them.
The slides began with the fires that the state is so famous for. Fires destroy vegetation, which holds the ground in place. The slides begin and recur when rain arrives. Mud clogs the culverts and can cover the road, making repairs imperative.
"We worked closely with Caltrans to map ‘cuts' to the hillside, leading down to a ‘bench' which would stop the material should it start to slide," O'Connor said. "Caltrans provided equipment that would tell us when the moisture in the ground increased and indicate if another slide might be imminent."
The bench was about 400 ft. above S.R. 1.
Specialized Equipment
A contractor, Access Limited Construction, brought in John Henry Drills to drive 55 mi. of 1½-in. steel bars, some up to 60 ft. long, in a 5-ft.-by-5-ft. grid. This pattern linked the layers of the hillside together and reduced the risk of future slides.
O'Connor and his team also supervised "spider excavators," which could operate more effectively on the steep terrain than a normal excavator. Some areas were even difficult for the spiders to operate safely. So, O'Connor called in experts from Caterpillar.
Granite Construction photo
"They brought in a remote control Cat 340 excavator and two remote control D8 bulldozers," O'Connor said. "If the dirt unexpectedly collapsed, no one would be hurt because our people were operating the equipment by remote control from a safe place. Our reps from Cat showed our guys how to use the foot pedals and controls. It was very similar to the normal equipment, so our people caught on fast."
Workers finished the job by placing a welded wire mesh over the terraced hillside. The slope flattens out at the bottom. Any rocks that work loose will collect behind a concrete barrier wall close to S.R. 1.
The team, with assistance from Caltrans, also had to bring in explosives to remove one stubborn rock from the hillside. Again, safety was a priority, and the rock was removed without further limiting the excavation.
Granite Construction photo
The remote-controlled equipment was a boon to the Granite team in safety and production.
"I believe this experience could pave the way for future jobs up and down the coast," O'Connor said. "This approach keeps people out of harm's way and enables us to keep up with our production schedule. I think this technology is the way of the future."
O'Connor recalled a comment from one of the most experienced supervisors as the project reached the finish line, "He said this was the most complicated project he has seen in his 40 years on the job."
"The full reopening on Highway 1 marks a significant milestone of local, national and global interest," Caltrans Director Dina El-Tawansy said. "There are few, if any, more iconic routes not just in California, but anywhere in the world. Restoring access for residents and tourists boosts regional economies and reinvigorates the pride and cultural identity associated with one of the most scenic roadways on the planet." CEG
