At One Place

Driving

3 figures covering driving, fastest first.

What Typical Range Kind What is measured
Driver reaction to an expected event 850 ms 700 ms–1 s Reaction Alert driver, anticipating the need to brake; time from stimulus to the brake pedal moving.
Driver reaction to a surprise 1.35 s 1.10 s–1.80 s Reaction Unanticipated hazard — a car pulling out, an obstacle appearing; time to the brake pedal.
The 2.5-second road design figure 2.50 s 2.50 s–2.50 s Design value The perception-reaction time assumed when calculating stopping sight distance for road geometry.

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