A.   The driver of a motor vehicle carrying passengers for hire, a school bus, or a vehicle carrying hazardous material and required to stop before crossing a railroad, before crossing at grade any track of a railroad, shall stop the vehicle within fifty feet (50') but not less than fifteen feet (15') from the nearest rail. While stopped, the driver shall listen and look in both directions for an approaching train, and for signals indicating the approach of a train, and shall not proceed until the driver can do so safely.
   B.   No stop need be made at a crossing where a peace officer or a traffic control device directs traffic to proceed. No stop need be made at a crossing designated by an "exempt" sign. An "exempt" sign shall be posted only where the tracks have been partially removed on either side of the roadway. (2008 Code § 17-343)