[Dylan16807]

> At the point where a 30km/h car would have come to a stop, a 50km/h car still impacts with 30km/h.

At that point it's barely superlinear. That means instead of dropping by 30kph it dropped 20kph.

Personally I'd focus more on how even a linear increase in stopping distance is a problem when pedestrians are around.

> On the other hand, average speeds in populated areas usually are way lower than 30km/h, so lowering the top speed to 30km has negligible effect on travel times.

Negligible speed impact also means negligible safety impact.