Political advertising at transit district and parking authority facilities.

(b) No transit district or parking authority that allows the placement of any advertising, whether placed directly by such transit district or parking authority or by any third party or independent contractor, on or within its facilities, including, but not limited to, advertising on or within any vehicle, or on any bus shelter operated by such transit district, parking authority, third party or independent contractor, shall prohibit the placement of political advertising on or within such facilities.