California Code, Streets and Highways Code - SHC § 251

It is further declared to be essential to the future development of the State of California that the deficiencies on the State Highway System not a part of the California Freeway and Expressway System and deficiencies on connections to the State Highway System be corrected simultaneously with the highways in the California Freeway and Expressway System in proportion to the relative deficiencies and the needs of traffic service.