Stopping Distances and Reaction Times

Question 1

What is the thinking distance?

Answer 1

The distance the car travels in the driver’s reaction time (the time between noticing the hazard and applying the brakes).

Question 2

What 5 main impacts affect your thinking distance?

Answer 2

• Tiredness
• Alcohol
• Drugs
• Distractions
• Speed

Question 3

What is the braking distance?

Answer 3

The distance taken to stop once the brakes have been applied.

Question 4

What 4 main impacts affect your braking distance?

Answer 4

• Speed
• Mass of car
• Brake conditions
• Friction between tyres and road

Question 5

How do you calculate the stopping distance of a vehicle?

Answer 5

Stopping distance = Thinking distance + Braking distance

Question 6

What two methods can be used to measure reaction times?

Answer 6

1) Computer-based test (clicking a mouse when the screen changes colour).
2) Ruler drop test.

Question 7

What is the ruler drop test?

Answer 7

1) Sit with your arm resting on the edge of a table (so it doesn’t move up or down during the test).
2) Get someone else to hold a ruler so it hangs between your thumb and forefinger, lined up with zero.
3) Without any warning, the person holding the ruler drops it. Close your thumb and finger to try to catch the ruler as quickly as possible.
4) The measurement on the ruler at the point where it was caught is how far the ruler dropped in the time it took you to react.

Question 8

What is the typical reaction time for the ruler drop test?

Answer 8

0.2-0.6 seconds.

Question 9

Typically, what is the reaction time of an alert driver in a real situation?

Answer 9

1 second.