How far do you travel before you stop at 50 km/h?
40 metres — 15 m of thinking distance while you react, plus 25 m of braking. A full-force emergency stop halves the braking part to 12.5 m, so 27.5 m in total. Double the speed and the braking distance quadruples. Verified 2026-08-03.
The three formulas, once
- Reaktionsweg (thinking distance)
- (speed ÷ 10) × 3 — how far you travel in the one second before you brake.
- Bremsweg (braking distance)
- (speed ÷ 10)² — normal braking, once the brakes bite.
- Gefahrbremsung (emergency stop)
- (speed ÷ 10)² ÷ 2 — a full-force stop halves the braking distance, never the thinking distance.
- Anhalteweg (stopping distance)
- Thinking + braking. This is the number the exam asks for.
Drive the stop yourself
Set a speed and watch two identical cars react to the same hazard: yours, and a ghost doing exactly half your speed on the same metre ruler. The thinking distance grows in proportion. The braking distance does not — it grows with the square, so the ghost always stops in a quarter of the braking distance, never a half.
A Gefahrbremsung halves the braking distance. It never touches the thinking distance — your reaction time is the same whatever your foot does next.
1.0 s is the alert driver the Faustformel assumes. Tired, or two seconds into a glance at a phone, 1.5–2.0 s is realistic — and every extra tenth adds metres at full speed, before the brakes have done anything at all.
50 km/h on dry asphalt
0 m Hazard spotted
Playing in real time: the whole stop takes 4.6 s.
Reaktionsweg
15 m
thinking, 1.0 s
Bremsweg
25 m
normal braking
Anhalteweg
40 m
what the exam asks for
Gefahrbremsung
27.5 m
total, braking halved
Safe gap
25 m
half the speedometer
Car lengths
≈ 9
at 4.5 m each
Why the ghost car matters
Halving the speed to 25 km/h cuts the braking distance from 25 m to 6.3 m — a factor of ×4, not ×2, because the formula squares the speed. That single fact answers most speed questions in the test.
Two seconds on a phone
A two-second glance at 50 km/h is 27.8 m driven completely blind — before any braking starts. §23 Abs. 1b StVO allows a handheld device only with the engine off, and an automatic start-stop shutdown does not count as off.
The gap you keep
Half the speedometer, in metres: 25 m at 50 km/h. On country roads the reflector posts stand 50 m apart, so one gap between posts is the right distance at 100 km/h — and the visibility threshold for the rear fog light.
The Faustformeln are the taught, examinable model, and the exam marks them — but they are approximations, not physics. The wet, snow and ice multipliers here (1.6× / 3× / 6×) are teaching figures for how fast grip disappears, not statutory values. Real stopping distance also depends on tyres, brakes, load and gradient.
Dry road, one second of reaction
| Speed | Thinking | Braking | Stopping | Emergency stop | Safe gap |
|---|---|---|---|---|---|
| 30 km/h | 9 m | 9 m | 18 m | 13.5 m | 15 m |
| 50 km/h | 15 m | 25 m | 40 m | 27.5 m | 25 m |
| 70 km/h | 21 m | 49 m | 70 m | 45.5 m | 35 m |
| 100 km/h | 30 m | 100 m | 130 m | 80 m | 50 m |
| 130 km/h | 39 m | 169 m | 208 m | 123.5 m | 65 m |
Read the 50 and the 100 rows together: twice the speed, but four times the braking distance (25 m → 100 m). That is the whole argument for speed limits in one line, and the exam asks it in several disguises.
Where these numbers get tested
Distance questions carry 4 and 5 error points because they are the ones that decide whether a crash happens. Drill them directly, or read the rule they sit inside.
Common questions
What is the stopping distance at 50 km/h in Germany?
40 metres. Thinking distance is (50 ÷ 10) × 3 = 15 m, braking distance is (50 ÷ 10)² = 25 m, and the Anhalteweg is the sum. With a full-force emergency stop the braking half halves to 12.5 m, giving 27.5 m in total. These are the Faustformeln German driving schools teach and the theory test marks.
Why does braking distance quadruple when speed doubles?
Because the braking formula squares the speed: (v ÷ 10)². At 50 km/h that is 25 m; at 100 km/h it is 100 m, four times as far, even though you are only going twice as fast. Kinetic energy rises with the square of speed and the brakes have to dispose of all of it. This single fact is behind most speed-limit questions in the exam.
How much following distance do I need?
Half the speedometer reading, in metres — 25 m at 50 km/h, 50 m at 100 km/h. That is roughly the distance you cover in 1.8 seconds, close to the two-second rule. Outside built-up areas lorries over 3.5 t must keep at least 50 m at speeds above 50 km/h (§4 Abs. 3 StVO).
Original practice questions — not the amtlicher Fragenkatalog. Every question, sign description and scenario here is written by us and covers the same StVO rules as the official Klasse B test. We are not TÜV, DEKRA or a Fahrschule, and we do not reproduce the official catalogue. Road signs themselves are amtliche Werke (StVO Anlage 1–3). Rules checked against StVO and FeV on 2026-08-03.
Last updated: 2026-08-03