California Code, Health and Safety Code - HSC § 41011

(a) After a public hearing, the Sacramento district may adopt regulations to require owners or operators of public or commercial motor vehicle fleets, or both, including those operated by the state, to periodically submit information to the Sacramento district on the number and type of vehicles operated within the Sacramento district, including, but not limited to, the amount and type of fuel used, for use by the Sacramento district in ascertaining the contribution of these vehicles to air pollution emissions within the Sacramento district.

(b) After a public hearing, the Sacramento district may adopt regulations to require operators of public and commercial fleet vehicles, when adding vehicles to, or replacing vehicles in, an existing fleet or when purchasing vehicles to form a new fleet, to purchase low-emission motor vehicles and to require, to the maximum extent feasible or appropriate, that those vehicles be operated on a cleaner burning alternative fuel. Rules and regulations adopted under this section shall be applicable to vehicles operated by the state only when funds necessary to pay the costs to the state to comply with those rules and regulations have been appropriated for that purpose.

(c) For purposes of this section, “motor vehicle fleet” means 15 or more vehicles under common ownership or operation.