What is the purpose of using the handbrake when starting a bus?

Using the handbrake when starting a bus primarily serves the purpose of preventing rolling. This is essential, especially when the bus is parked on an incline or decline. When the handbrake is engaged, it secures the vehicle in place, ensuring that it does not move unexpectedly during the start-up process. This becomes particularly important for large vehicles like buses, which have a significant mass and can cause serious safety hazards if they begin to roll.

While there are other operational aspects to consider when starting a vehicle, the handbrake's role in maintaining stability and control cannot be understated. Engaging the handbrake ensures the driver can focus on the starting procedure without the added concern of the vehicle inadvertently moving, making it a critical safety measure.