What must a driver do when leaving a vehicle?

When leaving a vehicle, it is essential for a driver to ensure that the motor is turned off, the parking brake is set, and the vehicle is locked. This is important for several reasons:

1. Safety: Turning off the engine prevents any accidental movements or roll-away incidents that could occur if the vehicle is left in gear or has a malfunction. Setting the parking brake adds an extra layer of security, especially on inclines, to ensure that the vehicle remains stationary.

2. Prevention of Theft: Locking the vehicle is crucial to protect your belongings and the vehicle itself from theft. An unlocked vehicle is an easy target for criminals, so taking the time to lock it can help prevent potential loss.

3. Environmental Considerations: Leaving a vehicle running unnecessarily contributes to air pollution and unnecessary fuel consumption. Therefore, turning off the engine not only promotes safety but also supports environmentally responsible driving practices.

The other options do not address these critical safety and security measures adequately. For instance, turning on hazard lights is typically done in specific circumstances where the vehicle is hazardous or broken down, rather than as a standard practice when leaving a vehicle. Leaving the engine running poses several risks, including unauthorized use of the vehicle and increased emissions,