---
title: "Reaction times — driving"
description: "3 measured reaction and reflex times covering driving, each labelled as a reflex, a reaction or a design value. The distinction is the point."
url: https://atoneplace.net/reaction-time/driving/
site: "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. |

- [Driver reaction to an expected event](https://atoneplace.net/reaction-time/driver-reaction-expected/) — 850 ms
- [Driver reaction to a surprise](https://atoneplace.net/reaction-time/driver-reaction-surprise/) — 1.35 s
- [The 2.5-second road design figure](https://atoneplace.net/reaction-time/aashto-perception-reaction/) — 2.50 s

## Related pages

- [The basic senses](https://atoneplace.net/reaction-time/senses/)
- [Reflexes](https://atoneplace.net/reaction-time/reflexes/)
- [Sport](https://atoneplace.net/reaction-time/sport/)
- [Screens and input](https://atoneplace.net/reaction-time/screens/)
- [How it varies between people](https://atoneplace.net/reaction-time/people/)