The driver of any vehicle, and the motorman of any streetcar, shall obey the instructions of any official traffic-control device applicable thereto, placed in accordance with this article and state law, unless otherwise directed by a police officer, or other authorized emergency personnel, subject to the exceptions granted to the driver of an authorized emergency vehicle by § 20-306(C) and G.S. § 20-156. (Code 1976, § 7.36)