| I agree that such a move could be argued to be in the greater interest of the public. I don't believe it is a good idea though, it removes the freedom of a driver to drive away from danger, or be able to transport somebody in need to hospital more quickly. I accept these are occasions most drivers will never face but with increased cases of road rage I would feel less safe with a limiter in place.
I think it would be far more beneficial to concentrate on catching offenders in 20mph and 30mph zones where there is a real risk to endangering the lives of pedestrians and cyclists, not motorways etc. I would raise the speed limit on motorways to 80mph, but concentrate on those who unnecessarily aggressively tailgate (e.g. less than 3 to 4 metres at speed).
I drove on an unrestricted section of a German autobahn last week, with some cars driving at up to around 110mph and was impressed by the number of drivers who did not tailgate. | 
