 As an additional travel precaution, the OST has imposed a maximum 65 miles-per-hour speed limit on its convoys, even if the posted limit is greater.Although OST provides sleeper berths in all vehicles, federal agents (couriers) accompanying shipments are not to exceed 32 hours of continuous travel without then having 8 hours of uninterrupted, stationary bed rest.As of 2017, OST employed 322 couriers.