The two new mile-long tunnels of Devil's Slide, decades in the making, are scheduled to open to traffic Monday.
The bypass moves drivers away from a dangerous cliff-hanging roadway south of San Francisco to a state-of-the-art passageway that will divert a 1.2-mile stretch of the Pacific Coast Highway.
The tunnel project comes with a price tag of $439 million.
The two tunnels have 32 massive industrial fans to blow out toxic fumes in the event of a fire. There are 42 emergency call box stations and ten digital sign boards. There is a nearby control center where Caltrans will monitor activities inside the tunnels around the clock.
"We have just about every state-of-the-art safety system that is available," said Caltrans spokesman Bob Haus.
The Tom Lantos Tunnels, named after the late congressman, are the first tunnels built in California in more than 50 years. There are only a handful of tunnels under construction in the U.S. today, including the Alaskan Way Tunnel in Seattle, and the fourth bore of the Caldecott Tunnel, just 34 miles east of Devil's Slide in the eastern San Francisco Bay area.
Devil's Slide is known for closures. Each time that happened it turns a 7-mile sce
nic drive from Pacifica to Half Moon Bay into a 45-mile detour.
In addition to slides, every year there are serious sometimes deadly accidents on the narrow roadway, which twists so sharply that safe drivers are forced to slow to less than 25 mph. Reckless motorists have plunged hundreds of feet down the cliffs or drifted into oncoming traffic, resulting in horrifying head-on collisions.
Plans are to turn the road, once closed, into a pedestrian and cycling park.
Last February, Caltrans estimated the tunnels would open to traffic December 2012. But the litany of small jobs piled up.
Whatever that date is, locals are looking forward to the stability the tunnels are expected to bring to the janky stretch of Highway One between Pacifica and Half Moon Bay.
"It is really going to help bridge the two communities together,"said Courtney Conlon, head of the Pacifica Chamber of Commerce. "They can go up down the coast without having to worry about safety issues."
Conlon said nearby residents are also excited about plans to convert the bypassed stretch of Highway One into a coastal walking and biking trail. Conlon said Pacifica plans to run a shuttle service to take visitors, along with their surfboards and bicycles, up to the trails.
"That's probably going to be the most panoramic view," said Conlon.