oops, I misspoke in this thread... the Cal Div Hwys logo disappeared sometime between Jan and May 1957. I've seen a '57 sign with a logo.
been doing a lot of research into signing practices in the 1950s - there's about 40 (!) different official changes in signing practice between 1947 and 1963, ranging from the easily evident (change from white-background to black-background guide signs in 1948) to the extremely subtle (change from 2/3 ratio of lowercase letters compared to uppercase letters, to 3/4 ratio sometime around Oct '57)... just a lot of information to dig through!
