South Yorkshire's chief constable caught speeding

Yesterday a Chief Constable was in the news for speeding, he was doing 90mph in a 60 limit. This officer had also been, according to the news, "the top traffic policeman in the country", which means he held meetings rather than actually did police work.
But there is one angle that the news did not look at. If the top traffic cop was doing 90mph then you can kind of assume it must have been safe at that time to be doing that speed on that road.
The news found the usual dippy woman from some road campaign to say how "speeding kills and she should have known better", as I have said on news groups, speed does not kill; inappropriate speed kills.
There are many people who are a danger doing 20mph but I expect the chief constable will have done some police driver training and will be a far better driver than the average.
The one thing this case has highlighted is that speed restrictions are stupid. They are arbitrary and there is no actual reason that 60 is safer than 90 and the "doing 70 saves X% petrol than doing 80 or 90" is rubbish.
People kill not speed. If it was simply speed then having driven legally at up to 140mph on many roads I should have died years ago. The dippy blond doing 30 on the school run, cell phone in one hand handbag on the lap looking for dinner money is the risk, the 70year old who can not see that doing 30 in a 60 is frustrating the hell out of every other driver is a risk, the idiot reading a map driving a 38 tonne truck is a risk, not the well trained driver doing an appropriate high speed concentrating on the road.