California Code, Vehicle Code - VEH § 9250.12

(a) For purposes of this section, “county” means the City and County of San Francisco.

(b) In addition to any other fees specified in this code and the Revenue and Taxation Code, a fee of four dollars ($4) shall be paid at the time of registration or renewal of registration of every vehicle registered to an address within a county, except those vehicles expressly exempted from payment of registration fees and commercial vehicles weighing more than 4,000 pounds, unladen, if all of the following occur:

(c) The fee imposed pursuant to this section shall apply to any original registration occurring on or after the January 1 following the adoption of the ordinance pursuant to paragraph (3) of subdivision (b) and to any renewal of registration with an expiration date on or after that January 1.

(d) After deducting all costs incurred pursuant to this section, the department shall distribute the revenues to the county. The amount of revenues distributed by the department to the county shall be equal to the net amount of revenues received from that county that were derived from the imposition of the additional fees.

(e) Money allocated to the county pursuant to this section shall be expended only to fund programs for the provision of public transit, including capital outlay, security, and maintenance costs, and including, but not limited to, removal of graffiti from public transit vehicles and facilities, and to pay the costs of compliance with paragraph (3) of subdivision (b).

(f) If public transit fees are increased at any time the additional registration fee authorized by the section is in effect, the fee may not continue to be imposed. This section shall become inoperative on the date those fares are increased and shall be repealed on January 1 next following that date. The board of supervisors shall notify the department of any increase in public transit fares occurring while the additional registration fee is in effect.