US 99 Los Angeles-Redlands corridor

[Max Rockatansky]

I finished a blog on the 1926-34 corridor of US 99 between Los Angeles and Redlands.  Early US 99 largely multiplexed US 66 on Legislative Route Number 9 between Pasadena and San Bernardino.  There is a ton of things and a lot of vagueness going on around Los Angeles with US 99 much like early US 66 had an issue with.  I made my best attempt sort everything out up to when US 99 was moved onto Legislative Route Number 26 directly from downtown Los Angeles to Redlands:

https://www.gribblenation.org/2022/01/the-1926-1934-los-angeles-redlands.html

[Max Rockatansky]

And here is the 1935-63 era route history of US 99.  Suffice to say there are a crap ton of pre-Interstate era freeways in this timeline:

https://www.gribblenation.org/2022/02/the-1935-1963-los-angeles-redlands.html

[mrsman]

Thank you again for your informative research and writing.

Here's a question.  As the Golden State Freeway was built in stages in the 1940s , 50s, and 60s, US 99 was not signed along the portion between the current I-5/CA 110 and I-5/I-10 interchanges until such time as the whole section was completed.  For most of the early freeway era, US 99 followed US 66 to the Four Level and then followed US 101 to the Ramona Parkway.

What number did the southern portion of the Golden State Freeway have (between I-5/I-10 and the East LA interchange)?  Was this always signed as I-5 (or future I-5) or was there another number during used during the early 1950s?  The 1963 state highway map seems to show a connected route from the eastern part of the Santa Monica Freeway, onto the Golden State Freeway and continuing norht.  But the map doesn't show the interstate highway numbers.  The part of GS south of the San Bernardino Fwy was never part of US 99, but it seems that it may have been part of LRN 4.  There may be no answer to this, unless it was known for the entire time that this section of GS Fwy (between San Bernardino Fwy and East LA interchange) was built that it was part of the Interstate Highway program.

[Max Rockatansky]

I've only ever seen it referred to as the "Golden State Freeway"  or LRN 4 prior to 1964.  Given the CHPW shows I-5 shields on segments of the same vintage I assume it was also signed as such.