Geo 1995 Prizm Owner's Manual page 69

If your speed drops below 20 mph (32 M),
or if the
Parking Brake
engine is not running smoothly, you should downshift to
the next lower gear. You may have to downshift two or
more gears to keep the engine running smoothly or for
good performance.
NOTICE:
To set the parking brake, hold the brake pedal down and
If you skip more than one gear when you
downshift, or if you race the engine when you
pull up on the parking brake lever. If the ignition is on,
the brake system warning light will come on.
downshift, you can damage the clutch
or
transaxle.