If anyone's interested, this book - often thought of as the "Master Plan of Freeways" - is available online courtesy of Los Angeles County Metro. I looked for this for years and came across it once before and now today. It can be downloaded in PDF form and might be nice to have in case it ever gets taken off line. This was likely the first in a series of what was the dream plan for Los Angeles County before financial and political reality set in during the 1960s - 1990s.
http://libraryarchives.metro.net/DPGTL/trafficplans/1943_freeways_for_the_region.pdf