The board of trustees of any institution, by obtaining liability insurance as provided in N.C. Gen. Stat. § 115D-53, is authorized to waive its governmental immunity from liability for the death or injury of person or for property damage caused by the negligence or tort of any agent or employee of the board of trustees when the agent or employee is acting within the scope of his authority or the course of  his employment. All automobiles, buses, trucks, or other motor vehicles intended primarily for use on the public roads and highways which are the property of a board of trustees shall be insured at all  times with liability insurance as provided in N.C. Gen. Stat. § 115D-53 Governmental immunity shall be deemed to have been waived by the act of obtaining liability insurance, but only to the extent that the board is indemnified for the negligence or torts of its agents and employees and only as to claims arising after the procurement of liability insurance and while such insurance is in force. (1963, c. 448, s. 23; 1979, c. 462, s. 2.)