Highway 1 was constructed in 1937. It was routed around Pedro Point headland and through Devil's Slide to the south.
The history of its route is complex and packed with politics and activism. The connection between the Montara region and what would become Pacifica originally went over the western Montara mountain. The Ocean Shore Railroad later cut a path hugging the coastline, even tunneling through the tip of the headlands above San Pedro Rock. With the collapse of the railroad as a business and the route due to landslides, much of the most treacherous route was abandoned. But the upper section along Devil's Slide became the route on the new Highway 1 in 1937.
Many sections of the new Highway were built right onto existing Ocean Shore Railroad beds. Some remnants of the those railroad beds and later highway, can be seen south of the Thornton Beach area of GGNRA in Daly City.
The Devil's Slide section of the new road kept collapsing at a few very unstable sections along its route, closing this major California highway for weeks to many months.
The California Department of Transportation proposed a multi-lane highway over the top of the ridge line to solve this Devil's Slide collapse closures. This was met with great opposition by groups of people who favored a tunnel through the mountain, limiting increased traffic and minimizing scenic damage to the area. After much controversy and more than six years of construction, the Tom Lantos Tunnels were opened in 2013.
The old highway route along the dramatic coast was converted to a spectacular trail now part of San Mateo County Parks. The Devil's Slide Trail provides a wonderful extension of the California Coastal Trail and connects it to the Pedro Point Headlands from the south.
Thornton Beach HWY 1 Remnant. Photograph by Stephen Johnson
Coast Route over time. Graphic by Ken Lajoie
Campaign Bumper Sticker for Tunnel.
Tom Lantos Tunnels HWY 1. Photograph by Stephen Johnson