Simple answer... ANPR and SPECS in town.
If they were serious about speed it would happen.

Im not supporting it by the way, but see dangers in all the current methods.
Cushions cause people to swere down the road. After they were introduced on Church Rise, people now zig zag down the road.
The proper humps on Sunderland are so badly built that they can be heard ripping peoples cars apart where the road has dropped from beneath the hump.

Camera's as stated cause people to reaction brake and slow for a 30 metre period then speed back up.

Cameras = revenue generators (to a degree)
Humps/Cushions = an end of year spend to keep next years budget high.

Neither are an effective method.

SPECS and ANPR = constant speed monitoring, reduced average speeds. At the end of the day, speed, get caught, pay the price.