Stopping distance = reaction distance + braking distance
Reaction distance = speed × reaction time
Braking distance = speed² ÷ (2 × deceleration)
Stopping distance = (speed × reaction time) + [speed² ÷ (2 × deceleration)]
Use consistent units for speed, time, and distance
Convert speed to meters per second before calculating if needed
Convert reaction time to seconds
Use deceleration as a positive value
If using mph and feet, keep all values in the same unit system
Higher speed increases stopping distance
Longer reaction time increases stopping distance
Lower deceleration increases braking distance