Earlier quoted context omitted.
Yeah I moved a short distance in London to an area that is all 20mph and for me the most noticeable change is the reduction in noise levels (the limits in the previous area were generally 30mph). The new area feels so much more peaceful. It surprised me how much difference a 10mph drop makes.
It's also surprising how much safer that little speed change is for pedestrians/cyclists if they were to get hit. https://www.nullvisjonen-agder.no/images/grafikk/dodsrisiko-... Speed in km/h vs death rate. From about 10% death (90% survival) at 30 km/h (~18mph) to about 80% death (only 20% survival!) at 50 km/h (~31 mph)
Even in the most transparent of places, I don't really see decisionmakers explaining their decisions.