If you need to slow down while driving on a slippery road, the first thing you should do is:
Firmly apply your brakes.
Take your foot off the gas pedal.
Apply your parking brake.
Pump your brakes.
To slow down on a slippery road, you should first take your foot off the gas pedal. If you need to slow down even more, gently apply a slow, steady pressure to your brake pedal.