California Codes, Business and Professions Code - BPC, Division 3 — Professions and Vocations Generally, Chapter 2 — Advertisers, Article 8 — Landscaped Freeways, Section 5443.1

The department shall allow any lawfully erected display to be converted to or replaced with a message center at its permitted location provided the conversion or replacement 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. An advertising display converted or replaced with a message center pursuant to this section 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).