Definition
Reaction time is the interval between when the driver perceives a hazard and when they begin to act (brake, swerve). For an alert, rested person it is about 1 second. It grows with fatigue, alcohol, drugs, sleep deprivation, phone use and distractions.
Key facts
- Average reaction time in good conditions: ~1 second.
- At 90 km/h, the car travels 25 m during that one second.
- Alcohol multiplies reaction time by up to 5.
- Phone use multiplies crash risk by 4, mostly through reaction time.
Practice real questions on this topic
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In the DGT exam
- As a usual guide, when does blood alcohol concentration tend to reach its maximum after drinking?
- How does cannabis affect driving?
- A tired driver...