When the power take-off is activated and the pump engaged, what speed should the vehicle speedometer show?

When the power take-off (PTO) is activated and the pump is engaged on a fire apparatus, the vehicle speedometer should display 0 mph. This is because the purpose of engaging the PTO is to use the vehicle's engine power to drive the fire pump, which requires the vehicle to be stationary. Activating the pump while the vehicle is in motion can lead to mechanical failure or unsafe operational conditions, as the pump is designed to operate at specific speeds and conditions that are achieved only when the vehicle is not moving. Therefore, it is essential for the safety of the operator and the effectiveness of the pump that the vehicle remains at a complete stop when the PTO is engaged and the pump is in use.