The second regular episode of the California Highways Route by Route podcast is up at either https://caroutebyroute.org/2022/08/13/episode-1-02-building-a-state-highway-system-the-1920s/ or https://anchor.fm/caroutebyroute/episodes/CA-RxR-1-02-Building-a-State-Highway-System-The-1920s-e1mffor . This one covers the history of the California State Highway system in the 1920s, and features an interview with Joel Windmiller on the US Highway System.
Subsequent episodes in Season 1 will cover the rest of the history of the system's development (the 1930s and war years; the 1950s and early 1960s, the great renumbering and 1960s, and the post 1960 period), how various highways in the state are numbered, highway naming, and organizations. Season 2 will start going route by route through all the highways (we have a sample up of that format for Route 105).
Details on the show are on the show page at https://caroutebyroute.org/2022/08/13/episode-1-02-building-a-state-highway-system-the-1920s/ . We're looking for interviews for future episodes. There's a list of the show page; let me know if you have any suggestions or leads.
As always: Ready, set, discuss.