1930s

Black and white image of sloping coastline with a highway winding along it.

1937

State Route 1, also known as the Pacific Coast Highway, was completed and served as an important tourist and commercial corridor. This is was California's first complete north-south highway.
Spectators and automobile parade celebrating opening day of the San Francisco-Oakland Bay Bridge – Nov. 12; 1936.

1936

The San Francisco–Oakland Bay Bridge opened to traffic. The bridge represented a remarkable engineering and political achievement.

Online Archive of California - Construction Photographs of the San Francisco-Oakland Bay Bridge, 1931-1936
California Route Shield Original Design

1934

The state sign route numbering system was adopted.