Hours of service of drivers employed by contract carriers transporting employees in the course of their employment. A contract carrier shall limit the hours of service by a driver transporting employees in the course of their employment on a road or highway of this State in a vehicle designed to carry 15 or fewer passengers to 12 hours of vehicle operation per day, 15 hours of on-duty service per day, and 70 hours of on-duty service in 7 consecutive days. The contract carrier shall require a driver who has 12 hours of vehicle operation per day or 15 hours of on-duty service per day to have at least 8 consecutive hours off duty before operating a vehicle again.