Cal. Veh. Code § 12517.45
(a) A person shall not operate a motor vehicle described in subdivision (k) of Section 545 while transporting school pupils at or below the 12th-grade level to or from a public or private school or to or from public or private school activities, unless all of the following requirements are met:
(1) The person has in his or her immediate possession all of the following:
(2)