The distance a vehicle travels between the time that you notice a hazard and the time that you start to brake is known as

Total stopping distance is the sum of your perception distance (how far the vehicle goes from when you see the hazard until your brain processes it), reaction distance (how far the vehicle goes from when your brain orders your foot to move onto the brake pedal until your foot actually starts to brake), and braking distance (how far the vehicle continues to travel once you apply the brake).