California Code, Vehicle Code - VEH § 23251

(a) The Department of the California Highway Patrol shall provide for proper and adequate policing of all toll highways and all vehicular crossings to ensure the enforcement thereon of this code and of any other law relating to the use and operation of vehicles upon toll highways, highways or vehicular crossings, and of the rules and regulations of the Department of Transportation in respect thereto, and to cooperate with the Department of Transportation to the end that vehicular crossings be operated at all times in a manner as to carry traffic efficiently.The authority of the Department of the California Highway Patrol is exclusive except as to the authority conferred by law upon the Department of Transportation in respect to vehicular crossings.

(b) Notwithstanding subdivision (a), a private operator of a toll highway may make temporary arrangements, not to exceed 30 days, for traffic law enforcement services with an agency that employs peace officers as described in Section 830.1 of the Penal Code, if the Department of the California Highway Patrol cannot fulfill its responsibilities as described in this section, as determined by the Secretary of the Business, Transportation and Housing Agency.

(c) The services provided by the Department of the California Highway Patrol for all toll highways that are operated by a private entity shall be reimbursed pursuant to Section 30809.1 of the Streets and Highways Code. If the private operator of a toll highway and the Department of the California Highway Patrol reach an impasse in negotiating an agreement for reimbursement, the Secretary of the Business, Transportation and Housing Agency shall assist in resolving the impasse.