Cal. Pub. Util. Code § 5392.3

Notwithstanding any other provision of law, any charter-party carrier of passengers that contracts to provide a vanpool vehicle, as described in paragraph (1) of subdivision (c) of Section 17149 of the Revenue and Taxation Code, to an employer or a group of employees for the purpose of operating that vehicle for transportation to and from work shall maintain protection against liability with respect to that vehicle in the same form and amount as described in Section 5391.2.