Stopping Distance Calculator

Total stopping distance = reaction distance + braking distance. Reaction distance = speed × reaction time (about 1.5 s). Braking distance = v² ÷ (2·g·(μ ± slope)), where μ is tyre-road friction: about 0.7 dry, 0.4 wet, 0.2 snow, 0.1 ice. Doubling speed quadruples the braking distance.