Cal. MVC § 484.6

The State Treasurer shall act as trustee for the department and the holders of the revenue bonds, to receive and disburse all the revenues applicable to the payment of the principal of or interest on the revenue bonds, including any reserve fund, sinking fund, or other fund or account established for further securing the revenue bonds. The department may provide in any resolution of issuance for the appointment of a trustee other than the State Treasurer to represent and enforce the rights of holders of the revenue bonds if, and in the manner and under conditions provided in the resolution authorizing the revenue bonds, such trustee is a bank or trust company duly qualified to do business in this state.