Cal. Veh. Code § 38165

(a) The department shall determine the size, color, and letters or number of the plate or device issued pursuant to this division and the life of the series of plate or device issued, but in no event less than six years. The design of the plate or device shall have the identification number as the most prominent feature of the device. During the intervening identification periods for which the plate or device is issued, the department shall issue a tab, sticker, or other suitable device to indicate the term for which such plate or device will be valid.
(b) On or before July 1, 2009, the department, in conjunction with the Division of Off-Highway Motor Vehicle Recreation of the Department of Parks and Recreation, shall report to the Assembly Committee on Water, Parks and Wildlife and the Senate Committee on Natural Resources and Water, regarding recommendations to improve the identification of off-highway motor vehicles. At a minimum, the report shall examine the benefits and challenges of all of the following:
1. (1) Using multiple identification stickers for each vehicle.
2. (2) Using large-print identifying numbers or letters.
3. (3) Various identifying devices, such as license plates and stickers.
4. (4) Requiring license plates or other device alternatives for certain off-highway vehicle types.
5. (5) Including a unique number for special nonresident permits issued under Section 38087.5.
(c) In preparing the report, the department and the Division of Off-Highway Motor Vehicle Recreation shall work with vehicle manufacturers to evaluate feasibility.