Shouldn't speed bumps be designed that you move over them at the speed allowed there, e.g. 30 km/h? So theoretically there wouldn't be a slowdown, unless you're already going faster than allowed.
At least I haven't seen speed bumps in 50 km/h roads just to slow people down.
Should, probably, but it's common in Central Europe that on a 50km/h road, there are 2 speedbumps that can't be safely passed if you're going over 25km/h.
Here in germany, mostly due to tech that allows speed-bump avoidcance, most villages and citys use a sort of slalom that by virtue of physics enforces a speed limit.
Also beloved are narrowings to one lane, where you can not see until you are really close up, wethere somebody from the other side is entering the lane.
At least I haven't seen speed bumps in 50 km/h roads just to slow people down.