Sure, but city streets are already mixed traffic. There are pedestrians, bikes, vehicles parking or turning, etc. It's not reasonable to raise the limit to what people want to drive and just ignore all the other users of the street.
Also, the optical narrowing mentioned in a sibling comment is quite effective. They've done that on a few streets near me via things like sidewalk bulb-outs at intersections, and swapping the parking lane & bike lane (so it goes curb-bike-parking-drive, rather than curb-parking-bike-drive). Everyone drives more slowly on those streets now - myself included.
For more, see https://www.vox.com/the-big-idea/2016/11/30/13784520/roads-d...
The trick is to make people feel like driving fast is unsafe, without actually making driving any unsafer.
Exactly. That is why we should ban all cars anywhere there is people, and they should be limited to highways. Because safety is most important, right? Right???
Itβs very simple, put speed cameras on every corner, and fine in terms of day wages. E.g., one week of your income as fine for going x% above.
Several countries are doing parts of this already, or moving towards it.
The vast majority of people just go however fast they feel comfortable (considering conditions, etc) regardless of the speed limit.
Mixed traffic speeds decrease safety.
Raising speed limits so that you don't have the % of people who comply with the letter of the law traveling slower than the people who go however fast they're comfortable usually improves safety.
Unless your goal is to increase ticket revenue or appease the "think of the children crowd" there's no point to lowering speed limits. It doesn't do much to affect traffic speed. To do that you have to modify the road or do something to change the traffic flow.
Self driving cars will improve safety because they'll result in political pressure to raise speed limits to match reality and they'll make dynamic speed limits more practical.