Braking and stopping distances

The total stopping distance consists of the reaction distance plus the braking distance. With an average reaction time of 1 second you travel 14 metres at 50 km/h before you start braking. At 50 km/h the total stopping distance is approximately 28 metres, at 80 km/h approximately 57 metres and at 100 km/h approximately 84 metres. Wet roads, fatigue and alcohol significantly increase both reaction time and braking distance. Worked example at 50 km/h: 50 km/h is about 14 metres per second. So with a 1-second reaction time you cover roughly 14 metres of reaction distance. The braking distance on dry tarmac at this speed is also about 14 metres, together approximately 28 metres. On a wet road surface the braking distance can roughly double, pushing the total stopping distance to about 40 metres or more. So keep to the 2-second rule: pick a fixed point beside the road and make sure you pass it at least 2 seconds after the car in front — more in rain or poor visibility.