Under GB/T 22485-2021, when is a cruising taxi driver required to press down the taximeter flag / activate the meter at the start of a trip?

1. As soon as the driver sees a pedestrian waving their hand on the sidewalk
2. Only after the passenger is safely seated inside the vehicle, doors are closed, and the vehicle begins to move forward
3. Immediately after dropping off the previous passenger while searching for the next hire
4. Five minutes after boarding to give the passenger time to adjust their luggage