The Department of Transportation may designate particularly dangerous highway crossings of railroads and erect stop signs at those crossings. When a stop sign is erected at a highway crossing of a railroad, the driver of any vehicle shall stop within 50 feet but not less than 15 feet from the nearest rail of such grade crossing and shall proceed only upon exercising due care. Any person who violates this section shall be guilty of an infraction and punished in accordance with N.C. Gen. Stat. § 20-176 Violation of this section shall not constitute negligence per se. An employer who knowingly allows, requires, permits, or otherwise authorizes a driver of a commercial motor vehicle to violate this section shall be guilty of an infraction. Such employer will also be subject to a civil penalty under N.C. Gen. Stat. § 20-37.21 (1991, c. 368, s. 1; 2005-349, s. 13.)