A pretty good description of why this happens https://www.strongtowns.org/journal/2021/8/6/the-key-to-slowing-traffic-is-street-design-not-speed-limits https://

A pretty good description of why this happens https://www.strongtowns.org/journal/2021/8/6/the-key-to-slowing-traffic-is-street-design-not-speed-limits https://www.strongtowns.org/journal/2021/8/6/the-key-to-slow... TLDR is the simpler you make a road, the faster and less attentive drivers are. While a complex cobblestone alleyway might be very tricky to navigate, basically no one will be killed there because you wouldn't attempt to speed while looking at your phone on it.