Stephen wrote:
I would like to ask all of you motorists this question.
What speed do you think that you should be able to drive at in a 30mph limit before you get prosecuted,forget about things like,time of day dry road, no pedestrians etc,concentrate on the actual speed limit.
This is a very important question, but it's a question that has no answer. We have to learn from the fact that no adequate answer is possible and adapt our approach.
The process of prosecution is intended to punish riak-causing behaviours. As such it should be educational. It must send a message about risk. Unfortunately there's no fixed relationship between speed-over-the-limit and risk.
Therefore the right threshold for prosecution is when, in the opinion of a police officer, the speed in excess of the speed limit is also inappropriate and risky in the immediate circumstances.
Take 3 cases of 40mph in a

.
1. Urban dual carriageway. 5am. Bright daylight. Deserted. NSL zone 200 yards ahead. No junctions. Guard rails on both sides. Straight. As close to a zero hazard environment as you could wish.
2. Normally busy urban arterial road. Single carriageway. Wide road, wide pavements. Well streetlit. No parked vehicles. School on left, but it's 3am and the place is deserted.
3. As number 2 except is now 8:45am. Car are parked and there are kids all over the place going to school.
Now let's say you're going through these zones in a marked job car in an emergency. I'm guessing you would find yourself doing something like:
1. 80mph
2. 65mph
3. 15mph
30mph speed limits just aren't created equal...