Devil’s Slide was a stretch of Highway 1 prone to landslides, and a major slide in 1983 and a five-month closure in 1995 renewed calls for a fix. Plans for an inland bypass were fought for decades, and in 1996 San Mateo County voters approved Measure T by 76 percent, changing the county’s stated preference from the bypass to a tunnel.
Boring began in September 2007, and the northern bore broke through on September 30, 2010. The tunnels, about 4,149 feet northbound and 4,008 feet southbound, are the second and third longest road tunnels in California. They carry the name of Congressman Tom Lantos, who helped secure funding.
The old highway has since been turned into a trail for hikers and bicyclists.
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