Sts. & Hy. Code, § 30684

After all bonds issued for the construction of the toll bridge and all bonds issued for refunding of the bonds and for additions, betterments, and extensions to the toll bridge, including new and additional approaches thereto, have been fully redeemed and paid, the commission shall continue to collect tolls and other revenues for the use of the toll bridge for the purpose of repaying the respective accounts from which money has been transferred pursuant to Section 30682. The amount so repaid to any such account shall be returned to the particular portion of the account from which it was transferred and shall be apportioned or allocated from the account and expended as if the transfer had not been made.

Upon repayment of all the accounts, the bridge shall thereafter be maintained and operated free of tolls or the rate of tolls shall thereafter be so adjusted as to provide a fund of not to exceed the amount necessary for the proper operation, maintenance, and insurance of the toll bridge under economical management.