Reaction, braking and stopping distance
| Speed | Reaction distance(m) | Braking distance (dry)(m) | Braking distance (wet)(m) | Stopping distance (dry)(m) | Stopping distance (wet)(m) |
|---|---|---|---|---|---|
| 30 km/h — living zone, school zone | 8.3 | 4.3 | 6.9 | 12.7 | 15.3 |
| 50 km/h — built-up area | 13.9 | 12.1 | 19.3 | 25.9 | 33.2 |
| 80 km/h — outside built-up area | 22.2 | 30.9 | 49.4 | 53.1 | 71.6 |
| 100 km/h — expressway, motorway by day | 27.8 | 48.2 | 77.2 | 76 | 104.9 |
| 130 km/h — statutory maximum, art. 21 | 36.1 | 81.5 | 130.4 | 117.6 | 166.5 |
Notes
- Where these numbers come from. There is no statutory table of braking distances. These values are calculated from three assumptions we state openly: reaction time 1.0 s, deceleration 8.0 m/s² on dry and 5.0 m/s² on wet road. Formulas: reaction distance = v · t, braking distance = v² / (2a), stopping distance = the sum. With other tyres, another road surface or an inattentive driver the outcome differs — the exam tests the relationship, not the digits after the decimal point.
- Why quadratic and not linear. Braking means getting rid of kinetic energy, and that energy is ½mv²: it grows with the SQUARE of the speed. Twice as fast is four times the energy, hence four times the braking distance. The table shows this exactly: 12.1 m at 50 and 48.2 m at 100 — precisely a factor of 4.0.
- The trap almost everyone falls into. "Twice as fast is four times as far" applies only to the BRAKING distance. The stopping distance goes from 25.9 to 76.0 metres, a factor of 2.9 — not 4. The reaction distance simply grows linearly, because you react for just as long, only you cover more metres in that second. Anyone who mixes up the three terms consistently gets this type of question wrong.
- Three words that do not mean the same thing. Reaction distance: the metres you cover before your foot touches the pedal. Braking distance: the metres from the moment the brakes bite until standstill. Stopping distance: the sum of the two, and that is the only figure that matters on the road.
- What the law does say about it. Art. 19 RVV names no figure at all, but places the duty on you: you must be able to bring your vehicle to a stop within the distance you can see and which is clear. Driving 100 in dense fog with 40 metres of visibility breaches art. 19 even if a "100" sign is posted.
The law itself
- RVV1990 art. 19
«De bestuurder moet in staat zijn zijn voertuig tot stilstand te brengen binnen de afstand waarover hij de weg kan overzien en waarover deze vrij is.»
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