Notwithstanding the provisions of subsection A of § 15.2-2000, localities may authorize owners of property with roadside vegetation described in § 15.2-2009.1 or buildings or structures encroaching under, upon and over any public rights-of-way therein, within such limitations as the localities may prescribe, to maintain such vegetation or encroachments as they exist, until such vegetation, buildings, or structures are destroyed or removed; however, nothing contained in this section shall be construed to relieve the owners of negligence on their part on account of any such vegetation or encroachment.