When operating dedicated school transport in Austria, what is the driver's legal responsibility regarding passenger escort personnel (Schülerbegleitpersonen)?

1. The driver may depart without the escort provided all children are seated
2. The driver must cooperate with assigned school escorts, ensure the escort is on board before departure, and confirm children remain seated safely before moving the vehicle
3. The driver may delegate responsibility for the children entirely to the escort
4. The driver need not check the escort is on board, since that is the school's responsibility