I did some OpenStreetMap work recently with aerial imagery in the US in such a suburb and was a bit surprised to see that the streets where people lived (not arterial roads through the suburb) were about 10 m wide. I feel the residential streets here with 5.5 m are already a bit too wide, and the main road through the village (with bus traffic and until recently lots of traffic to the motorway) is about 7 m wide.

That people tend to speed when you build a road as if it were a 100 km/h rural road doesn't seem too surprising, sadly. Now, as a parent I still think people are driving too fast, especially around the kindergarten (30 km/h speed limit doesn't automatically make that the desired default speed for that street), but it's probably night and day compared to American suburbs.