This report provides an overview of methods to prevent drowsy driving of drivers. Several preventive approaches were discussed such as the use of questionnaires, campaigns and fatigue management plans. A search for law enforcement instruments to prevent sleepiness at the wheel did not provide any instruments that could detect sleepiness of drivers objectively and reliably at present. There were four different driver groups defined which among the awareness of fatigue and drowsiness should be promoted professional drivers in the domain of freight traffic, professional drivers in the domain of passenger traffic, private drivers and drivers with sleeping disorders. The main part of the report focused on the state-of-the-art regarding drowsiness detection technology.