California Code, Business and Professions Code - BPC § 5443.5

Nothing in this article prohibits the Department of Transportation from allowing any legally permitted display situated on property being acquired for a public use to be relocated, subject to the approval of the public agency acquiring the property and the approval of the jurisdiction in which the display will be relocated, so long as the action of the department in allowing the relocation of the display 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 which do not conform to this article within the jurisdiction of a governmental entity.