Even with the caveats about limited data and untangling causation and correlation, the statistics are striking: the first year of a scheme in Wales where the speed limit on urban roads was lowered to 20mph resulted in about 100 fewer people killed or seriously injured.
I have personally found that roads are nicer to walk along with people going slower, but I haven’t necessarily noticed more people walking. I think part of the issue is the way that new housing has been built where it is still a significant distance away from the places you need to get to is still keeping people in cars.
I have not noticed any differences in the lighting, but the Welsh Gov did postpone all road building projects at a similar time, and for any smaller residential road building I would’ve thought the builders would want it to be low speed anyway.