I completely agree.

You can't enforce a speed limit by simply placing a speed sign and hoping everyone is going to magically follow them. More cops or speed cameras isn't going to work either.

My city is currently working on a plan to lower the speed limit from 50kmh to 30kmh (30 mph to 18 mph). The entire thing is a multi-year program because it essentially means redesigning those roads from scratch.

A road which has been designed for its speed limit doesn't even need a speed sign - the driver will naturally be driving at that speed already because anything faster will feel unsafe to the driver.