Final answer:
When there are no apparent hazards on the scene of an accident, the ambulance should be parked approximately 50 feet away.
Step-by-step explanation:
When there are no apparent hazards on the scene of an accident, the ambulance should be parked approximately 50 feet away. This distance ensures the safety of the ambulance crew and provides room for any potential hazards that may arise. It also allows for a clear path for other emergency vehicles and personnel.