There are at least (and a few more) two kinds of speed 'bumps'. There are those that are about a foot wide and are officially (as my city engineer explained to me) called 'bumps' These are quite jarring and are good for controlling speeds below 15mph - often found in school zones. There are also what are known as 'humps' which are more like 3ft wide and can be traveled over at about 25mph. These are (around here) used very frequently on residential streets. These 'humps' are very comfortable to fly over on a bike even over 25mph.
I bring this up as 'humps' should always extend across the full width of the road, even across a bike lane if it exists. Otherwise (I deal with this sometimes) drivers will very often, at least more than half of them swerve their car right into the bike lane, which can has lead to close calls for me (which is one reason I don't ride in BL on those streets). Fortunately most of these 'humps' extend the full width of the pavement.
'Bumps' on the other hand are painful to go over on a bike over ~10mph. BUT - 'bumps' should only be used in special cases (i.e. 15mph school zones) and not on normal slow flow streets. And on any street that is posted at such a low speed (i.e. 15mph) it should not have a BL anyway. A solution I've proposed to city is to make a 12"-18" wide cut in the bump in the middle of the travel lane so a cyclist can pass thru while keeping up with 15mph traffic flow, that way the 'bump' can extend all the way to the curb and prevent cars from swerving sideways against curb to avoid half of bump.

Al