The slight speed increase that ordinary people do does not kill people.
We aren't talking about people going freeway speed in a residential area.
We aren't talking about people going freeway speed in a residential area.
https://safety.fhwa.dot.gov/speedmgt/ref_mats/fhwasa1304/Res...
K = m v²
That energy increases with the square of the speed, and has to go somewhere (person's body) in a collision.