California Code, Streets and Highways Code - SHC § 30153

All such bridges, transportation facilities, and additional transportation facilities or portion thereof shall be built by the department in accordance with The State Contract Act insofar as the provisions of that act are applicable, except that the amount of the cash, bidders' bonds, or certified checks required to accompany any bid submitted, when bids relating to the construction of any bridge or highway crossing, transportation facilities, or additional transportation facilities are called for, shall be fixed and determined by the department.