Cal. Bus. & Prof. Code § 5218

“Penalty segment” means any segment of a highway located in this state which was not covered by the Federal Aid Highway Act of 1958 and the Collier-Z'berg Act but which is covered by the Highway Beautification Act of 1965, namely, any segment of an interstate highway which is constructed upon right-of-way, any part of the width of which was acquired prior to July 1, 1956, and any segment of a primary highway.