How it is calculated
g is taken as 9,81 m/s². ABS, the tyres, and a slope all shift the formula. This is not a crash report.
Distance = v × t + v² / (2μg)
Where the numbers come from
- Speed — unit in the field: km/h
- Reaction — unit in the field: s
- Surface
Example
At 60 km/h, a 1 s reaction, and dry asphalt with μ = 0,7, the full stopping distance is about 37 m.
Questions
Speed in km/h?
Yes, the calculator converts it to m/s.
Is a 1-second reaction typical?
A common textbook example. A tired driver takes longer to react.
Is black ice at μ = 0,1 too optimistic?
On smooth ice the grip can be even lower. Treat the field as an order of magnitude.