What pedal must a driver depress while starting a vehicle with a manual transmission?

When starting a vehicle with a manual transmission, the driver must depress the clutch pedal. This is essential because the clutch disengages the engine from the transmission, allowing the vehicle to start without the risk of rolling forward or backward. By pressing the clutch, the driver ensures that the gears are not engaged, which is crucial for a smooth and safe start.

If the driver were to attempt starting the vehicle without pressing the clutch, the engine would still be connected to the transmission. This situation could lead to an accidental lurching of the car, posing a safety risk to the driver and others nearby. Thus, the requirement to depress the clutch pedal serves a vital safety function in operating a manual transmission vehicle.