In a car with a manual transmission, the driver must downshift by moving the gearshift lever to a lower gear. This will cause the engine to run at a higher RPM, which will provide more engine braking and help to slow the car down.
In a car with an automatic transmission, the transmission will automatically downshift when the car is slowing down, if the transmission is in "sport" or "manual" mode. These modes allow the driver to have more control over the shifting process, and they can be used to downshift the transmission manually if desired.
Downshifting can help to slow a car down more quickly, and it can also help to prevent the car from downshifting too quickly, which can cause the engine to stall.
