Reaction time, attention time and total time

Understanding time components helps explain why we need margins. This article defines reaction time, attention time and total time in the driving process.

Overview

Definitions

  • Reaction time: hazard detection to starting action
  • Attention time: time needed to perceive and understand a situation
  • Total time: perception + decision + action

Timeline

Practical implications

  • More complex scenes increase attention time
  • Expect longer times at night, in bad weather and when tired
  • Leave space and reduce speed to compensate