Comment by Xylakant

The other thing is the squared taper-off of speed when braking and I used to not think about this until someone showed the math. If you're going 30km/h and a kid jumps out 10 meters in front of you, you can just barely come to a stop. If you're going 50 km/h, you'll run them over with 30km/h remaining speed and come to a stop about 10m further down.