(a) The Traffic Engineer is authorized to place markers, buttons or signs within or adjacent to intersections indicating the course to be traveled by vehicles turning at such intersections, and such course to be traveled as so indicated may conform to or be other than as prescribed by law or ordinance.

(b) When authorized markers, buttons or other indications are placed within or adjacent to an intersection indicating the course to be traveled by vehicles turning thereat, no driver of a vehicle shall disobey the directions of such indications, except when otherwise directed by a law enforcement officer. (Code 1981 § 43-197. Code 1995 § 142-236.)