Highways and the Caldecott Tunnel

Highways 13 and 24 surround Lake Temescal, and are part of a complicated history of roadways and tunnels linking Alameda and Contra Costa counties. The original pathways for horse drawn buggies over the hill were steep and quite treacherous. Interest began as early as 1860 in constructing a tunnel through the mountain, but a variety of business issues kept it from completion until the early 1900s.

Originally a small, one-way bore called the Kennedy tunnel connected the two sides of the mountain. Like the Lake Temescal dam, it was built mostly with Chinese manual labor. However, it was plagued with size issues as buggies became cars, and met with constant landslide and flooding issues. in the late 1920s it was decided to create the Broadway Tunnels (later the Caldecott Tunnels) below the Kennedy Tunnel, and construct a new roadway to direct traffic through them. The first two bores and the road that would eventually become Highway 24 were opened in 1937. The Kennedy tunnel was sealed 10 years later in 1947.

Additional bores were added in 1964 and 2013 to facilitate the every growing need for greater Bay Area car traffic.