Agree with me or not but this is my opinion.
I think it could be a good idea if implemented to the first, say, 3 to 5 years of getting a license.
On motorways it could mean an end to traffic as everyone will travel at exactly the same speed, but no overtaking is the downside, you will enter the motorway behind a car and stay there until you come off.
In built up areas especially by schools and shopping centres etc, it's an idea that should have been used many years ago.
How many times have you done 35 or even 40 in a 30, I know I have, maybe lapsed judgment, but I have. Touch wood no accidents as yet.
Slate me if you wish but I am on the fence about this idea of speed restrictions. In some areas of driving I think it's brilliant. But in others a terrible idea.