California Code, Streets and Highways Code - SHC § 113

Upon a request from the department the governing body of any city may acquire any real property or interest therein needed for state highway purposes and lying within such city.  The title to such real property or interest therein may be taken in the name of the State or of the city.

Any city may aid in the construction, improvement or maintenance of any state highway located in whole or in part within its boundaries by contributing any part of the expense thereof to the department out of any city funds available or to become available for construction, improvement or maintenance of streets within the city.