Re: exceeding the speed limit is OK?
My personal view is that the safe speed to drive at is based on the condition of the road, the vehicle, the driver and the weather, as well as the possibility of hazards.
This means that there are many occasions when the SAFE speed is actually a fraction of the number written at the side of the road. e.g. A narrow street in a residential area, with cars parked both sides, during a school holiday, is a crawl down the road exercise, as you will not see the kid until he is stood infront of your car, regardles of the 30mph signs. (*)
Conversly, if you are on a motorway, with no traffic visible in either direction, the speed you drive at is not really an issue.
What we need is less focus on speed, and more focus on dangerous driving and due care and attention. Unfortunately this has to be done with people, and not gadgets.
(*) this is not a random example, and i have seen police vehicles going down this street in these condition at more than a safe speed.