The Pacific Coast Highway Structures - Mega Structure.

The Pacific Highway auto trail became British Columbia Highway 99 from Vancouver to the Canada–United States border, U.S. Route 99 from the border to Red Bluff, California, in the Sacramento Valley; U.S. Route 99W from Red Bluff to Davis, California, in the Central Valley; U.S. Route 40 from Davis to San Francisco; and U.S. Route 101 from San Francisco to San Diego. This alignment is now mostly Interstate 5 in California, except between Woodland, California, and Los Angeles, where it uses State Route 113, Interstate 80 and then U.S. Route 101.
In Oregon, Interstate 5 is now officially the Pacific Highway No. 1 (see Oregon highways and routes). First completed in 1923, Oregon's Pacific Highway was the first border to border paved highway west of the Mississippi River.

Read More: https://en.wikipedia.org/wiki/Pacific_Highway_(United_States)