No person shall operate any motor vehicle within the boundaries of a county park, including beach areas, except upon roads, streets, highway, and parking areas: PROVIDED, That certain types of motor vehicles may be operated on park trails where such trails have been specifically designated by the parks division and posted for use by such vehicles. (Added by § 5 of Res. adopted Apr. 22, 1974; Amended by Ord. 86-011 § 2, Feb. 26, 1986; Amended by Ord. 93-066, Aug. 18, 1993, Eff date Aug. 28, 1993).