No person shall drive, cause to be driven or permit any vehicle having an unladen weight in excess of 5,000 pounds to be driven on any portion of Iris Canyon Road that lies within Iris Canyon Park, as such park is described in that certain deed from Margaret Jacks, et al, to the City, dated January 24, 1946.

Vehicles owned by any government agency, and vehicles owned by any public utility, while engaged in repairing, installing, maintaining or inspecting any public utility, shall be exempt from the provisions of this Section.