This is a very old article, and unlike the main article on roundabouts it is not regularly updated. The technical detail is still correct, but references to Chalfont Drive test centre are not.
The article “How To Do Roundabouts” is very popular, and I add to it regularly based on search terms people use to find it.
I wanted to mention a particular example as a separate article. It happened the other day and is a prime example of how signalling using the “12 o’clock rule” can be dangerous and misleading.
Remember that there is no such thing as the “12 o’clock rule”.
I was on a lesson with a pupil and we were looking at the big Nuthall roundabout in Nottingham. This roundabout scares the wits out of most pupils, and the stories they hear about it have made it legendary for the terror it generates.
But it isn’t just pupils who have issues with it. I drive through it regularly and I’m not exaggerating when I say that more than 50% of people who use it haven’t got a clue how to do it properly. These people make it harder for pupils (and anyone doing it the right way) as they swing wildly 
across several lanes because they’re not in the correct one to begin with (and that’s true of many roundabouts).
My pupil had just approached it for the first time on this lesson. We’d come in from the A6002 and were intending to leave via the A610 towards the City Centre. The image on the left represents the sign you see on approach.
Note how the A611 is shown at 12 o’clock and the A610 at 3 o’clock (i.e. a long way after 12 o’clock).
Also note how the roundabout is oval, which illustrates another problem with the 12 o’clock rule – it assumes roundabouts are round like a clock face, which many aren’t. But it is enough for this example to point out that the roundabout sign would demand that you signal right for the A610 if the “12 o’clock rule” actually existed.
Anyway, the A6002 approach is a single lane, but as you come to the roundabout it opens into four lanes. The two left ones are for the M1. The third is for the B600, and the right hand lane is for the B600, A611, and A610 (plus that little blip which represents a minor road (5th exit) into a housing estate). There is a lane sign and lane markings to explain this, but as I say it’s a 60mph road, and these signs and markings only appear very close to the roundabout, so you need to be able to choose your lane quickly to avoid having anyone behind box you in as they over- or undertake you.
There is no way any instructor would – or should – be expecting their pupil to be able to negotiate this on their test without having been taught how to do it properly. If anyone out there is being taught by such an instructor, they should change to another one quickly, because they’re wasting their money. And it IS on at least one test route at Chalfont Drive.
On the lesson, my pupil had moved into the right hand lane for the A610 on approach. She’d already attempted to indicate once, but I’d stopped her. In front of us was another learner with their right indicator on. As we pulled up behind my pupil again tried to signal – I stopped her and said “you’re copying that learner! Stop it!”
Now, as we pulled up behind that learner car my thoughts were that he or she was either going into the housing estate or doubling back along the A6002 (I often do that when I’m covering this roundabout on lessons so we don’t have to drive miles to try it again). For all the world, that’s what the indicator was telling me.
The Nuthall roundabout is huge and light controlled at several points as you go around it. As you emerge on to the roundabout from the A6002 the right hand lane splits into two options at the next set of lights – the left of these is B600 and A611, the right (innermost) one is A611, A610, housing estate (and full circle). We needed the innermost lane, and the learner in front went there too – still signalling.
When you move through this second set of lights the roundabout now opens into a huge expanse of road – FIVE lanes, and lines everywhere. If you follow your set of lines for the A610, that alone opens into two lanes to choose from, and the right hand one of these also has the choice of two more which open out to the right for carrying on around – and these also split up to another set of lights. At one point – admittedly with small islands to segregate traffic – there are SEVEN LANES side by side. It isn’t easy for anyone.
As we followed our A610 lines in the left hand lane, and with clear “straight ahead” arrows on the road by this stage, the learner in front continued to signal right – all the time I was concerned that they would swing across into one of the three lanes to our right (and the additional worry that my pupil would copy – which she has a habit of doing). Every indication was that they wanted to go right. Their signal was highly misleading, particularly when you consider the number of supposedly experienced full licence holders who routinely close their eyes, put their foot down, and hope for the best when they negotiate this roundabout!
The whole point is that at no stage of taking the A610 from the A6002 via the Nuthall roundabout do you NEED to signal. Only the “12 o’clock rule” says you should – but a signal is totally unnecessary for most routes because it has clear lane definitions (big white arrows and huge letters telling you where it goes). There might be occasions where on the approach you’ve left it a little late to move into the right hand lane and a signal tells whoever’s behind you’re moving over, or perhaps you could signal purely to note your intention to take a particular lane option where there are two available, or if you got into the wrong lane and want to change then you could signal.
But signalling just for the roundabout itself is extremely misleading – no matter what the non-existent “12 o’clock rule” says.