Cal. Sts. & Hy. Code § 100.51
Notwithstanding any provision of Section 100.5, whenever any bridge or highway crossing over a navigable waterway in this state, including, but not limited to, toll bridges or other toll highway crossings built or acquired under the provisions of the California Toll Bridge Authority Act, is closed to traffic because of accident thereto or repair thereof or is for any reason unable fully to accommodate traffic, the department may operate a vehicular or passenger ferry as a substitute therefor. In the operation of such vehicular or passenger ferry, the department may impose a toll for passage. For the purpose of imposing such toll, the department may employ any reasonable classification of vehicles, including, but not limited to, classification by weight, length, or number of axles.
Ca. Sts. and High. Code § 100.51