From the October 24, 2014, Shorpy site: "Circa 1925: Man pointing at California State Automobile Association signage."
"Woman with pennant reciting, 'Boost the Redwood Highway.'" A souvenir from the early days of motoring, when signage was a do-it-yourself affair, with routes marked and mapped by automobile clubs.
The top sign reads, with arrow pointing to the left, "Garberville 39 5/10, Dyerville 70, Eureka 117."
Bottom sign reads, with arrow pointing left, "Bell Springs 12, Harris 24 Willits 38.
A comment says that the photo was taken at or near the intersection of Bell Springs Road and the current US-101 (Redwood Highway) about ten miles north of Laytonville.
The state of our roads before the U.S. Highway System was superinposed on the existing routes.