Stopping Distance Calculator - Reaction Time Tool

Total stopping distance combines reaction distance (traveled while your brain processes the danger and your foot moves to the brake) plus braking distance (from brake application to stop). This calculator includes both components for realistic safety planning.

1. 1

   Enter Speed

   Input vehicle speed in mph or km/h

2. 2

   Set Reaction Time

   Enter reaction time (average 1.5 seconds, more if tired or distracted)

3. 3

   Select Surface Conditions

   Choose road conditions affecting braking friction

4. 4

   View Total Distance

   See breakdown of reaction and braking distances

• 1

  Reaction distance is often larger than braking distance at highway speeds

• 2

  Distracted driving can double or triple normal reaction time

• 3

  Always leave more space than minimum calculations suggest for safety margin

• 4

  Night driving requires extra distance due to reduced visibility

• 5

  Heavy vehicles need significantly more stopping distance than cars

• Ignoring reaction distance which dominates at higher speeds

• Using average reaction time when tired (can be 2-3 seconds or more)

• Not adjusting following distance for changed road or visibility conditions

• Assuming emergency braking performance matches normal braking