rubbish, councils install humps, however they dont have the power to change the speed limit.
it requires an act of parliment.
the speedlimit for an urban road illuminated with with lights less than 200yrds apart.
is 30mph, unless otherwise indicated.
I live near a school and the authorities are encouraging folks to slow down by fitting flashing speed monitors that show your speed as you approach them.
They use red lamps when you are exceeding the limit and green when below the limit. The limit is set at 20mph. The compulsory speed limit for the road however is 30mph.
There are no speed bumps on my road although there are road narrowing pedestrian islands in the centre.