Tenn. Code Ann. § 55-8-121: No-passing zones

The department of transportation is authorized to determine those portions of any highway where overtaking and passing or driving to the left of the roadway would be especially hazardous and may by appropriate signs or markings on the roadway indicate the beginning and end of those zones. When these signs or markings are in place and clearly visible to an ordinarily observant person, every driver of a vehicle shall obey the directions thereof.