Stopping Distances

40mph after drinking during wet weather

You were under the influence of alcohol, driving at an excessive speed, and the road was wet, so you hit the pedestrian.

The excessive speed increased both your thinking distance and braking distance. The wet weather reduced your car's grip on the road, and increased your braking distance whilst the alcoholic impairment increased the time it took you to spot, and react to, the pedestrain. All three of these factors significantly increased your overall stopping distance.

Any of these three factors would have caused the vehicle to hit the pedestrian but all three in combination have resulted in a serious injury.

Thinking Distance
Braking Distance
Overall Stopping Distance

Injury: Yes, the car hit the pedestrian.

In this scenario, the most likely outcome would be a fatal or serious injury. Half of the pedestrians hit in these conditions would be killed. Only one in every ten pedestrians would avoid a serious injury.

Suggested Comparisons

  1. Speed increases both the thinking distance and braking distance, although the effects of alcohol and the wet weather meant that in this instance, a lower speed would not have avoided the collision. You can re-run the simulator at a lower speed, without drink-driving or wet weather, to see how much the stopping distance is decreased.
  2. Using a mobile phone also increases the thinking distance as the driver takes longer to spot and react to the pedestrian. Re-run the simulator, and select mobile phone use instead of alcoholic impairment, to see how this changes the result.
  3. Wet weather increases braking distances. Re-run the simulator, and select dry weather, to see how this decreases the braking distance.

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