The original California State Route 117 was a segment of Junipero Serra Boulevard from Crystal Springs Road in San Bruno north to Interstate 280 in Daly City. The corridor of Junipero Serra Boulevard reached San Bruno by 1952 via development as part of Joint Highway District Number 10. During 1956 Junipero Serra Boulevard was added to the State Highway System as part of Legislative Route Number 237. The adopted corridor the Junipero Serra Freeway and Interstate 280 north of San Bruno was selected by the California Highway Commission during 1960. This action led to existing Junipero Serra Boulevard being reassigned as California State Route 117 as part of the 1964 State Highway Renumbering. California State Route 117 was deleted during 1965 and Junipero Serra Boulevard was reassigned as a placeholder routing for Interstate 280 until the completion of the Junipero Serra Freeway north of San Bruno during 1970.
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