The Devil's Slide tunnels, twin bores 4,200 feet long in Pacifica, Calif., will be opened to motorists early this week. The $439 million project is the first highway-tunnel project in the state in nearly 50 years. "It just seems unreal to me," said Zoe Kersteen-Tucker, a project advocate. "We worked on it for so many years. Now we not only have a state-of-the-art tunnel but we've protected Montara Mountain and all these beautiful coastal hills forever."