California Code, Revenue and Taxation Code - RTC § 8608

(a) “User” includes any person who, within the meaning of the term “use” as defined in this chapter, uses fuel.

(b) Article 1 (commencing with Section 8701) of Chapter 3 and Article 1 (commencing with Section 8751) of Chapter 4 do not apply to (1) a user whose sole use of fuel in this state is for the propulsion of a privately operated passenger motor vehicle, a commercial vehicle with unladen weight of less than 7,000 pounds, or a privately operated two-axle truck which the user has rented or leased for a period of 30 days or less; or (2) an interstate user whose sole use of fuel in this state is for the propulsion of a motor vehicle that is not a qualified motor vehicle and is operated in connection with an interstate trip; if the fuel used, except fuel brought into this state in the fuel tank of the vehicle, is purchased from and delivered into the fuel tank of the vehicle by a vendor.

(c) When the board determines that it is necessary for the efficient administration of this part to regard any lessor of vehicles as the agent of the lessee, with regard to the equipment leased, the board may so regard the lessor and may qualify the lessee as the user for purposes of this part.