Cal. Bus. & Prof. Code § 7574.22

A person registered as a proprietary private security officer shall carry on his or her person, while on duty, a valid and current proprietary private security officer’s registration card or a hard copy printout of the bureau’s approval from the bureau’s Internet Web site and either a valid driver’s license issued pursuant to Section 12811 of the Vehicle Code or a valid identification card issued pursuant to Section 13000 of the Vehicle Code.