The last Metropolitan Los Angeles Freeway Plan post here, showed a bunch of freeways that never got built. this is a prior plan, and, instead of freeways, it shows an abundance of parkways (whatever those are). In the west San Fernando Valley, it shows the “Ventura Parkway,” which looks like it runs along Ventura Boulevard.
It shows Sepulveda, but it is not designated a parkway. Other parkways are Whithall in the Valley, and Santa Monica on the Westside.
A larger and complete 1947 map will show you the plan for the whole L.A. Metro area.
It is interesting to see how transportation planning evolved for cars, and that in 1947, freeways were not part of that planning vocabulary yet. Previous post, showing 1958 plans: www.conejopost.com/archives/10683