What are the statutory requirements for Emergency Exits (Notausstiege / Issues de secours) in a Category D passenger bus under VTS Article 69?

1. Only the main front passenger door is required as an exit
2. Emergency exits are required only on double-decker buses
3. Emergency exits must be welded shut to prevent theft
4. Buses must have designated emergency exits on both sides of the vehicle (service doors, emergency doors, push-out or breakable safety glass windows with nearby emergency hammers), as well as emergency roof escape hatches