Wikipedia:WikiProject U.S. Roads/California/History/Temporary signage of Interstates

Until many Interstates were completed, the old alignments that had that legislative number were signed as a different route:

I-5

• US 101, Mexico to Los Angeles
• US 99, San Fernando to Wheeler Ridge
• US 50, Mossdale to Stockton
• US 99W, Woodland to Red Bluff
• US 99, Red Bluff to Oregon

I-105

• SR 42

I-205

• US 50

I-505

• Apparently signed as I-505 despite not being a freeway

I-605

• SR 35??

I-8

• US 80

I-10

• US 60, Beaumont to Arizona

I-210

• Nothing, Newhall Pass to San Fernando
• SR 118, San Fernando to Pasadena
• SR 134 in Pasadena?
• US 66, Pasadena to Glendora

I-15

• US 66, San Bernardino to Barstow
• US 91, Barstow to Nevada

I-40

• US 66

I-80

• US 40

I-580

• US 50, Oakland to Tracy

I-680

• SR 238, San Jose to Mission San Jose
• SR 21, Mission San Jose to Cordelia