Proximity of portable scale to commercial grain elevator - Exceptions. A portable scale used at any location other than an official weigh station by the Department of Public Safety or the Corporation Commission to weigh any vehicle transporting grain shall not be located within two (2) highway miles of any commercial grain elevator. This section shall not apply if the vehicle is:
1. Involved in a collision;
2. Being subjected to a Commercial Vehicle Safety Alliance (CVSA) inspection by the Department of Public Safety; or 3. Operated on any highway of the national defense highway system.