Braking distance is how far a vehicle travels while decelerating to a stop, set by speed and tire grip.
Braking Distance = v² ÷ (2 × μ × g)
Where
| v | Speed at the start of braking |
| μ (mu) | Tire-to-road friction coefficient (about 0.7 dry, 0.4 wet) |
| g | Gravity, 9.81 m/s² (32.2 ft/s²) |
Worked example
At 27 m/s (about 60 mph) on dry asphalt: 27² ÷ (2 × 0.7 × 9.81) = 729 ÷ 13.7, about 53 m of braking.
Total stopping distance adds reaction distance — speed multiplied by reaction time (around 1.5 s) — before braking even begins.
Use the Brake Distance calculator to include reaction distance.