Work-related fatigue is a threat to safe transport, but little has been done to structure the complex array of possible mitigating measures that risk managers can consider. To improve the situation, we review the literature to identify and explain 15 countermeasures types, which we then group into five different hazard levels along a “fatigue risk trajectory”. The resulting model helps to structure the choice of countermeasures that together form barriers to fatigue development. The final barrier structure will depend not only on the nature of the transport operation and hazard to be mitigated, but on the resources available to the employer, the current approach to safety risk management, and the scope of fatigue risk management required. Finally, the report identifies questions that need to be answered to improve fatigue management in future transport operations.