Cal. Government Code § 3599.66

(a) If a memorandum of understanding has expired, and the employer and the recognized employee organization have not agreed to a new memorandum of understanding and have not reached an impasse in negotiations, subject to subdivision (b), the parties to the agreement shall continue to give effect to the provisions of the expired memorandum of understanding, including provisions that supersede existing law, arbitration provisions, no-strike provisions, and agreements regarding matters covered in the federal Fair Labor Standards Act of 1938 (29 U.S.C. Sec. 201 et seq.). (b) If the employer and the recognized employee organization reach an impasse in negotiations for a new memorandum of understanding, the employer may implement any or all of its last, best, and final offer through adoption of a resolution. Implementation of the last, best, and final offer does not relieve the parties of the obligation to bargain in good faith and reach an agreement on a memorandum of understanding if circumstances change, and does not result in a waiver of rights that the recognized employee organization has under this chapter.