California Code, Vehicle Code - VEH § 4853

(a) The department may issue one or more stickers, tabs, or other suitable devices in lieu of the license plates provided for under this code.  Except when the physical differences between the stickers, tabs, or devices and license plates by their nature render the provisions of this code inapplicable, all provisions of this code relating to license plates may apply to stickers, tabs, or devices.

(b) The department may establish a pilot program to evaluate the use of alternatives to the stickers, tabs, license plates, and registration cards authorized by this code, subject to all of the following requirements:

(c) In the conduct of any pilot program pursuant to this section, any data exchanged between the department and any electronic device or the provider of any electronic device shall be limited to those data necessary to display evidence of registration compliance.  The department shall not receive or retain any information generated during the pilot program regarding the movement, location, or use of a vehicle participating in the pilot program.

(d) In the conduct of any pilot program pursuant to this section, the department may evaluate the inclusion of participants in the Business Partner Automation Program, pursuant to Section 1685.

(e) Subdivisions (b) to (d), inclusive, shall become inoperative on the effective date of any regulations adopted pursuant to subdivision (b) of Section 4854.