California Code, Business and Professions Code - BPC § 5412.4

Section 5412 shall not be applied in any judicial proceeding which was filed and served by any city, county, or city and county prior to January 1, 1982, except that Section 5412 shall be applied in litigation to prohibit the removal without compensation of any advertising display located within 660 feet from the edge of the right-of-way of an interstate or primary highway with its copy visible from the highway, or any advertising display placed or maintained beyond 660 feet from the edge of the right-of-way of an interstate or primary highway that is placed with the purpose of its message being read from the main traveled way of the highway.