It's obviously something that varies from one place to another. You live in a place where the blue rinses feature a lot and they are, inevitably, less prone to excessive speed than to simple attention wandering.
A nearby road here has NSL and is capable of high speeds despite being a country lane.
There's two types of driver, the slow and the fast.
Almost always, slower drivers simply create queues but sometimes people will attempt to overtake slower drivers and therein lies a problem. There's one overtaking place at the top, and one on the way up about halfway up. If you have enough speed at the top you can overtake reasonably slow cars before coming down the hill, and if you bide your time coming up the hill, and have a good uphill acceleration / plan it just right, you can overtake there too.
Anywhere else there is a risk, depending on how slow the other vehicle is.
If they were all willing to travel slowly there wouldn't be an issue but there are from time to time people who attempt to overtake someone who is not really going all that much slower than them, in a place that isn't really viable for the manoeuvre.
I assume that mostly they get away with this as there turns out to be nothing coming, but three or four times last year, there's been a coming together of two or three cars, in the section at the bottom of the hill where there is a straight section that tempts people into an overtaking manoeuvre but exposes them to the head on traffic coming down the hill the other way at what can easily be a significantly high speed.
This is the sort of "so long as nothing comes down there at 110 mph" where it all sounds silly until it happens to you and then you are in trouble because there's nowhere to go and the car you're overtaking has little chance of doing something helpful, they usually brake and thus deny you the chance to swerve in while under harsh braking (we've probably all been there in some similar situation.)
They're mostly good drivers in decent cars caught out by circumstance and the brakes come on, speeds come rapidly down, so the shunts are usually just wrecked cars and sometimes broken bones.
If the cars were all keeping to the speed limit (60 is the limit but really isn't a reflection of typical speeds) then these accidents simply wouldn't happen. If nobody overtook on the lower section, then the accidents wouldn't happen whether or not there was speeding.
When both happen, there are accidents and the accidents can be serious.
It's fair to say that the slow vehicles can include bluetops but mostly the oldsters are few and far between and cars roar up and down this road at reasonably impressive speeds. Also that most people who use it, realise they can't overtake and slow down when coming round the corner onto the lower straight, just in case someone with poor judgement is coming head on in their lane taking the chance that the road isn't clear.
There's not been a shunt for a while, as far as I've heard, since they put a big "no overtaking" hatching section on the straight part at the bottom and limited the first part of the bottom approach to 40. This seems a much better solution than hiding a speed camera in the bushes on the steep part of the hill on the way down, where there are never any accidents but the highest speeds are reached. Course, I still slow down just in case someone is ignoring the hatching and I have to emergency stop, BYMMV.