@ Anonymous Coward
"Conditions change with time as well as place. *That*'s what you and the strident nannies are ignoring.
Not all road speed limit decisions are taken in a rational, evidence-based environment. I can see why daytime speed limits like the A38 through Birmingham have dropped a bit over the years as traffic volume has increased, but when the road is empty (at 3 am), well-lit and wide, and a comfy speed in 5th is 40, why can the speed limit not increase? And be 50 on the expressway section?"
Oh, I agree that the speed limits can stand to be changed upwards in certain areas (motorways could definitely be a bit higher, for instance, as per certain more enlightened continental countries), and that a road can be safe to do 40 in at one time of day and only safe to do 25 at another, but I'd still much prefer that decision to be taken by the government or local authority than by the individual driver. How many people *under*estimate how good a driver they are? The person setting the speed limit also knows better than someone just passing through the area that although the first section of that 30 stretch looks like it's all country lane and safe to do 50, just around the corner is a zebra crossing in front of a school which at 50 you'd be unable to stop for.
I'd not trust 95% of drivers to make a decision on what speed they should be doing in a "rational, evidence-based environment", or even a fully informed one. There are precious few drivers who are as careful and unlikely to cause an accident as you say you are.
And in any event, from a legal point of view how on earth would you enforce a speed limit which is determined by the skill of the driver? How would you even determine it in the first place? "Dangerous driving" is a subjective enough offence as it is, without making one's speed entirely policed by that offence.
Far simpler, and easier to enforce, is to have set speed limits for set stretches of road. We all know what they are, and if you're in such a hurry that you'd need to consider speeding, then you should just have left a little earlier.
So - yes, we should increase one or two speed limits around the place, but anything more than just increasing certain set speed limits is going to be ridiculously impossible to police, and *will* lead to more accidents.