What should an omnibus driver do when approaching a flooded section of the road where the water depth is unclear?

1. Drive through at high speed to clear the water quickly
2. Stop the bus safely, assess the water depth, do not proceed if it exceeds the bus's safe wading depth (usually hub height), and notify BOCC
3. Instruct passengers to stand on the seats and drive through
4. Proceed immediately as buses are heavy enough to not float