California Code, Business and Professions Code - BPC § 5443

(b)(1) Any local governmental entity from entering into a relocation agreement for any purpose, including, but not limited to, those purposes provided inSection 5412, or the department from allowing any lawfully erected display to be increased in height at its permitted location or to be relocated provided the height increase or relocation would not cause a reduction in federal aid highway funds as provided in Section 131 of Title 23 of the United States Code or an increase in the number of displays within the state that does not conform to this article. Any increase in height permitted under this subdivision shall not be more than that necessary to restore the visibility of the display to the main-traveled way.Relocated displays may be placed in the same or a different city, county, or city and county, and relocation agreements shall be entered into between the sign and permit owner and the local governmental entity. An advertising display relocated pursuant to this paragraph shall be deemed a placement requiring a new permit and shall comply with all of the provisions of Article 6 (commencing with Section 5350) and Article 7 (commencing with Section 5400). A relocated display shall not result in a net increase of the number of displays adjacent to landscaped freeway segments statewide.

(2) A relocated advertising display may be converted to or replaced with a message center pursuant to a relocation agreement for any purpose, including, but not limited to, the purposes provided pursuant to Section 5412. The department shall issue a permit, without any additional consideration, for any display that is being placed pursuant to a relocation agreement with another governmental entity if the relocated display conforms with the provisions of this section.An advertising display converted or replaced with a message center pursuant to this paragraph shall be deemed a placement requiring a new permit and shall comply with all the provisions of Article 6 (commencing with Section 5350) and Article 7 (commencing with Section 5400).