History traces the bayshore from highway to freeway

The predecessor to the Bayshore Freeway had been the old Bayshore Highway. According to San Mateo County Historical Association records, parts of the Bayshore Highway had already been built by the 1920s. The highway represented an attempt to relieve traffic on El Camino Real, then the major thoroughfare between San Francisco and San Jose. By 1925, the Bureau of Highways started using a number system to identify highways to alleviate the confusion created by identifying roadways with proper names. Under the new system, El Camino Real, once called the County Road, became the first Highway 101.

Over the years the developing Bayshore Highway/Freeway began sharing the number 101 with El Camino Real, which for a time became known as the Highway 101 Bypass. In 1931, Redwood City hosted a parade to commemorate the completion of Bayshore Highway to Redwood City. The southern section to San Jose was finished in 1937. The route of the old Bayshore began at 10th and Market in San Francisco. It extended past the intersection at today's Cesar Chavez and Potrero. It continued along what is now Bayshore Boulevard, which parallels today's freeway until it intersects with Third Street.

From Third Street, the Bayshore Highway proceeded through one particularly infamous section of road known as