What are the three essential emergency action steps to take immediately when arriving first at a road traffic accident scene (the PAS protocol)?

1. Protect (Protéger), Alert (Alerter), Rescue (Secourir)
2. Rescue the casualties, then protect the scene, then alert the emergency services
3. Alert the emergency services, then move every casualty clear of the vehicles, then protect the scene
4. Photograph the damage, exchange insurance details, then alert the emergency services