California Code, Health and Safety Code - HSC § 40605

(a) The district board shall adopt a surcharge on the registration fees applicable to all motor vehicles registered in those counties within the district, as specified in Section 9250.16 of the Vehicle Code.

(b) Fees generated by the surcharge imposed pursuant to Section 9250.16 of the Vehicle Code shall only be used to reduce emissions from vehicular sources, including, but not limited to, the following activities:

(c) No more than 2 percent of the funds collected pursuant to the surcharge shall be used by the district for administrative expenses.

(d) The district board shall adopt accounting procedures to ensure that revenues from motor vehicle registration fees are not commingled with other program revenues.