What does Bhutanese law require of a driver on a stretch of road where a 'No Horn' sign is erected?

1. The horn may still be sounded to clear livestock and pedestrians from the road
2. The horn must not be used while facing the sign or anywhere inside the signed area
3. The horn must be sounded continuously when passing schools during class hours
4. The restriction applies only between 10:00 PM and 6:00 AM