California State Route 250 is a former State Highway located near the city of Anaheim. California State Route 250 was aligned from Interstate 5 near the Orange County Hospital via then Placentia Avenue (now State College Boulevard) to California State Route 91. California State Route 250 was deleted by the State Legislature during 1981 following the completion of the California State Route 57 freeway between Interstate 5 and California State Route 91.
https://www.gribblenation.org/2023/01/former-california-state-route-250.html?m=1
I saw the maps where CA-57 was originally intended to expand south of the Orange Crush Interchange.
But it's interesting how back then temporary State Routes used to be common at one point when freeway expansions were common.