U.S. Route 101
The nearly highway's northern terminus is in Tumwater, Washington: the route remains along the Olympic Peninsula's coastal perimeter west, north, and east; the northernmost point on the highway is in Port Angeles. The southern terminus of US 101 is in Los Angeles at the East Los Angeles Interchange, the world's busiest freeway interchange.
Gaviota Tunnel
The Gaviota Tunnel (officially known as the Gaviota Gorge Tunnel) is a tunnel on U.S. Route 101 (US 101, most portions between San Francisco and Los Angeles follow the old El Camino Real) completed in 1953 in the center of Gaviota State Park, northwest of Santa Barbara, California. It is long and tall. Only the northbound lanes of US 101 pass through it, as the southbound lanes descend from Gaviota Pass through a narrow canyon to the west of the tunnel. Because it is the only major route between the Santa Barbara County South Coast and the Santa Ynez Valley, bicycles are allowed through it. There is a rest area for both southbound and northbound lanes on the southern end of the tunnel, the southernmost one along U.S. Route 101.