Part of California's famed Highway 1 crumbles into the ocean

They built a tunnel to bypass devils slide. Now it's a pedestrian and bicycle path. On the Carquinez Strait there used to be a road that was abandoned due to landslides I think in the early 80's. Now is the George Miller Regional Trail.

It's more like highway built on fundamentally unstable coastal geology[1] falls into the ocean here and there.

[1] California is basically schmutz scraped off a subducting plate over the last 100 million years. Friend worked on a job where they excavated into a hillside behind a house and found a 10 inch wide crack filled with wet clay.

This coastline is incredibly unstable. They've done exceptional erosion control over the years, and only this much has happened.