This is a map of California's state highway system (constructed and proposed routes) as it existed in 1920. Routes are color-coded by how they were added: red for the bond issues (1910, 1916, 1919), with the darkest red in 1910, and black for roads added by legislative acts (1895-1919). If a road was legislated but also in a bond issue, it is shown as red. Email me if you would like a copy of the GIS data I created for the highways.
No machine-readable source provided. Own work assumed (based on copyright claims).
No machine-readable author provided. NE2 assumed (based on copyright claims).