30 km/h is the maximum speed allowed in many cities (and a growing number of them) and even in cities where 50 km/h is allowed, the average speed is apparently around 30 km/h when traffic is minimal (in France, according to [0]) and 15 km/h otherwise. I think it's safe to say that electric cars reduce noise in cities, in fact I can observe it every day myself from my house.

[0] https://www.francetvinfo.fr/replay-radio/le-vrai-du-faux/une...