Stopping Distance
What is Stopping Distance?
Your stopping distance is the total distance your vehicle travels:
-
From the moment you realise you need to brake, to
-
The moment your vehicle comes to a complete stop.
You must always leave enough space between you and the vehicle in front so you can stop safely if it slows down or stops suddenly.
To do this, you need to be able to judge your overall stopping distance.
Practising Distance Judgement
Improve your sense of distance by practising on foot:
-
Pick a point ahead and estimate the distance to it.
-
Walk the distance to check your accuracy.
(One good stride is roughly 1 metre.)
Factors Affecting Stopping Distance
Stopping distance depends on:
-
Speed – the faster you go, the longer it takes to stop.
-
Road gradient – stopping distance increases downhill.
-
Weather and road surface – wet, icy, or loose roads increase distance.
-
Vehicle condition – worn brakes or tyres reduce effectiveness.
-
Vehicle size and weight – heavier vehicles take longer to stop.
-
Driver reaction time – tiredness or distraction can slow reactions.
Components of Stopping Distance
Stopping distance is made up of two parts:
| Component | Description |
| Thinking Distance | Distance travelled while you react and move your foot to the brake. |
| Braking Distance | Distance your vehicle travels from the moment you press the brake until it stops completely. |
Thinking Distance + Braking Distance = Total Stopping Distance
Typical Stopping Distance (in good, dry conditions)
| Speed | Thinking Distance | Braking Distance | Overall Stopping Distance |
| 20 mph | 6 m | 6 m | 12 m |
| 30 mph | 9 m | 14 m | 23 m |
| 40 mph | 12 m | 24 m | 36 m |
| 50 mph | 15 m | 38 m | 53 m |
| 60 mph | 18 m | 55 m | 73 m |
| 70 mph | 21 m | 75 m | 96 m |
In wet conditions, double these distances.
On icy roads, allow up to 10 times the normal distance.