What sequence of checks must a bus driver perform before pulling out from a roadside bus stop?

1. Check interior and exterior mirrors, activate the turn indicator, check blind spots, and ensure pulling out will not endanger other road users
2. Immediately engage gear and accelerate into the lane relying entirely on other vehicles to stop
3. Flash the high-beam headlights and sound the horn before turning the steering wheel
4. Open the rear door to check traffic before accelerating