I find that I have more time to react to pedestrian’s or avoid collisions when I’m doing 30-40 km/h in a playground, school or residential area. The only problem is most times drivers behind me are inpatient. They honk or try to overtake. Classic Edmonton drivers.
There’s a few residential roads that should have stayed at 50 (mostly ones that end in “drive” or “boulevard”), but for the most part 40 is better. Hell, some roads would be better at 30!