Speed humps, sleeping policeman, speed cushions (slightly different), call them what you like I don't like them.
Had a council letter saying they are proposing to make it a 20mph zone along our street and this involves laying down speed cushions.
Buses and lorries use this road and it seems speed cushions will let them run between the cushions.
So while hunting for ammunition so I could write to them objecting to this idea I found this site -
http://www.abd.org.uk/speed_humps.htm