Speed bumps alone don't help, that is right. You also need to have raised pedestrian crossings, you need to reduce lane width (maybe even so narrow that you have to yield when a car is coming from the other direction), the street needs to not be straight, etc. The space you get from that can be used for trees, bicycle paths, broader sidewalks and such niceties.

If all of this is there you can't just ride 50 km/h through there because it just feels wrong. Of course this is an example where we go from a limit of 50 to a limit of 30, but similar ideas exist for going from 70 to 50 etc.