Why speed quadruples your stopping distance.
Braking distance grows with the square of speed — double how fast you're going and you need four times the road to stop, not twice. At 100 km/h on dry asphalt that's about 49 m of braking alone; on ice, nearly 400 m.
Speed v
d ∝ v²
10 km/hdouble v · 4× the braking distance200 km/h
Try
Braking distance follows d = v²/(2μg), from Newton's laws under a constant deceleration of μg — see Braking distance on Wikipedia. It assumes locked-wheel or ABS-optimal braking on a level, dry-modelled road, not any specific car's tires, load transfer, wear, or ABS tuning. The 1.5 s reaction time shown alongside it is a typical average: real reaction times vary by driver, and alcohol, fatigue, or a distraction like a phone can push it several times higher. Reaction distance plus braking distance gives total stopping distance — the number that actually matters on the road, not braking distance alone.