Braking distance and stopping distance

In short: The stopping distance is made up of reaction distance and braking distance. At double the speed the braking distance is about four times as long.

In more detail: The reaction distance arises because it takes about a second to react. During that time the car keeps rolling without braking.

In detail

• Rule of thumb braking distance: (speed in km/h ÷ 10)² on a dry road. At 50 km/h that is about 25 m.
• Rule of thumb reaction distance: (speed ÷ 10) × 3. At 50 km/h about 15 m.
• Wet and snow: The braking distance gets much longer, on snow often several times.
• Emergency braking: ABS prevents the wheels from locking; you press fully and keep the pedal down.
• Conclusion: Driving slower not only saves fuel but above all gains safety (abstand-halten-im-strassenverkehr).