Stopping Distances

30mph while using a phone during wet weather

You were using a mobile phone, and the road was wet, so you hit the pedestrian. Even though you were driving at 20 mph, using a mobile phone distracted you and increased your thinking distance. To make matters worse, the wet road also increased your braking distance. Both together significantly increased your overall stopping distance. This meant that you were not able to stop safely when the pedestrian stepped out unexpectedly.

Thinking Distance
19m
Braking Distance
18m
Overall Stopping Distance
37m

Injury: Yes, the car hit the pedestrian.

In this scenario, it is likely that the pedestrian would be killed or seriously injured. Only one in every five pedestrians would avoid an injury of any kind.

Suggested Comparisons

  1. This accident would have been prevented if the driver had not been using a mobile phone. The driver took longer to spot and react to the pedestrian, because s/he was distracted by using the mobile phone. This resulted in a longer thinking distance, which meant that it took longer to stop. Re-run the simulator, without selecting mobile phone use, to see how the thinking distance is reduced, but note how the wet road still increases the braking distance.
  2. Drinking alcohol also increases the thinking distance meaning that the driver takes longer to spot and react to the pedestrian. Re-run the simulator, and select alcoholic impairment instead of mobile phone use, 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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