Image 1

enter image description here

I have added 2 images showing the roundabout. There are two lanes on the approach to the roundabout, which lane does each one go into? So for example, if I was in the left lane, which of the 3 lanes do I enter? Do I enter the far left or the center?

  • 1
    Which country is this, out of curiosity? Oct 24, 2016 at 15:43
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    @DangerZone: I suspect that your inquiry is justified not only out of mere curiosity, but to make the question answerable in the first place. Different countries have different traffic regulations, and even harmonized regulations tend to differ especially in corner cases like complicated intersections. Oct 24, 2016 at 15:45
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    Had to remove 1 as I didn't have 10 repuation
    – Sam
    Oct 24, 2016 at 15:51
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    It would be the right two lanes. The left is for direct access to A509. Is there something that makes you think differently?
    – Johns-305
    Oct 24, 2016 at 15:55
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    Yes, what's missing is some guidance on who gets the middle land in the roundabout. Look at the Street View of the approach. There's probably some signs indicating which of those two lanes leads where.
    – Johns-305
    Oct 24, 2016 at 16:12

7 Answers 7


If you are in the left lane on the slip road, the island forces you to go left, signposted Newport Pagnell A509(n). If you go further down the slip road (see image) you can see that the slip road's middle and right lanes both have access to MK A509(s). So if you are in the middle lane on the slip road, you can go into the left or middle lanes on the roundabout. If you are in the right lane on the slip road, you must take the right lane on the roundabout.

enter image description here

Edit: I found some higher-res satellite imagery, so added image with lanes coloured to indicate what I said above, a bit clearer.

enter image description here

  • 1
    That google maps image does not correspond to the one in the question.
    – Moo
    Oct 24, 2016 at 18:19
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    @Moo - yes it does - htis answer's image is from a viewpoint a few yards back from the question's 1st image.
    – brhans
    Oct 24, 2016 at 19:15
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    Google maps is out of date. If you look at this roundabout on Google Maps satellite view, this slip road only has 2 lanes - the left-most lane hadn't been built yet. But Bing maps has more up-to-date satellite imagery. Oct 24, 2016 at 19:30
  • Your explanation and the road sign don't match your colouring. A user would have to change lanes to the right (to get on the "yellow" path) in order to head towards Milton Keynes. Oct 24, 2016 at 20:00
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    @Lightness I'm not sure I understand. When the driver gets off the M1, the slip road is 2 lanes and they can choose either (yellow or green). Both these lanes go into MK, and the left most (green) also lets you back onto the M1 if you got off accidentally. The red lane appears on the left about half way up, but at the begging of the slip road, the only options are green and yellow. Oct 25, 2016 at 7:57

Which lane you should be in at any point depends on where you want to go to, not where you've come from. Where there is more than one lane for your destination, be in the left-most of them unless it's already full (and you intend to pass the vehicles in it) in which case you can use the next one along.

Left-most lane (separated by the traffic island) turns left onto the A509 (Northbound).

Middle lane can go into the left lane on the roundabout (to go straight ahead, which in this case means back on to the M1 which you just came off) or middle lane on the roundabout (for MK / A509(S) - this is a right turn, but in this case the road markings before your first image indicate that this can be done from the middle lane).

Right-most lane can go into the right or middle lane on the roundabout (for MK / A509(S)).

If you go into the middle lane of the roundabout, be aware that you may not be the only one heading there!

  • This isnt quite correct - the middle entry lane should only go to the left most lane on the roundabout, it should not go to the middle lane on the roundabout. The rule is left lane (in this instance, the feeder lane doesnt count) for left turns or straight over, and the only reason to migrate to the middle lane on the roundabout is to take a right turn, and you should be in the right lane for that (unless otherwise signposted). In this case, the right entry lane is signposted straight on or right, so it can safely violate the normal rule.
    – Moo
    Oct 24, 2016 at 18:12
  • "be in the left-most of them unless it's already full in which case you can use the next one along." Only use the lane to the right if you are going to overtake people on the left. Do not lane hog. Please. Oct 24, 2016 at 18:14
  • Also this answer asserts things that are not true for all roundabouts. For example, the "main" exit may have three lanes and be on the right-hand side, but might be attached to the left-hand lane regardless. Oct 24, 2016 at 18:15
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    Oh, and furthermore, it doesn't answer the question. The OP doesn't want to know which lane they must end up in, but which lane is "attached" to the one they're coming from (and, consequently, will they be transferring between lanes?) Oct 24, 2016 at 18:17
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    @Moo If you take the left lane of the roundabout, you get forced onto the southbound M1, which is the road you just left to take the roundabout in the first place. Therefore, the expectation cannot be that lane 2 of the sliproad filters into lane 1 of the roundabout. Oct 24, 2016 at 22:41

I've lived in the MK area since I was born. My family and I have used this roundabout countless times, and this is how we use it.

If you're coming at the turn from the M1, and you want to go to:

  • A509 -- Go in the left lane. Exit the roundabout.
  • M1(S) -- Go in middle lane. On the roundabout the left lane.
  • MK(S) -- Go in middle lane. On the roundabout the middle lane.
  • A509(S) -- Go in the right lane. On the roundabout the right lane.

If you're coming at the turn from the A509, and you want to go to:

  • A509 -- Go in the left lane. Exit the roundabout.
  • M1(S) -- Go in the left lane. On the roundabout the left lane.
  • MK(S) -- Go in the right lane. On the roundabout the middle lane.
  • A509(S) -- Go in the right lane. On the roundabout the right lane.

Here is a visual:

enter image description here

  • This diagram is correct :)
    – Alnitak
    Oct 25, 2016 at 16:44

On approach to the roundabout you have three lanes:

  1. the left most lane, which is a feeder lane to the first exit and thus can be excluded from the answer.
  2. the middle lane
  3. the right lane

On the roundabout, you have three lanes:

  1. The left lane, which goes straight on
  2. The middle lane, which goes both straight on and right
  3. The right lane, which goes right

The correct answer is that approach lane 2 (the middle lane) goes only to roundabout lane 1 (the left lane) while the approach lane 3 (the right lane) goes to either the roundabout lane 2 or 3 depending on how far around the roundabout the driver intends to go.

Thats the only acceptable use of those lanes.

See on the following image my very skillful depiction in MS paint of the junction with more of the roundabout. The purple line allows you to rejoin the A509 in the direction you came from, if you so wish, as well as allowing you to take the MK exit.

MK Roundabout

To see the continuation of the yellow and purple lanes, I have followed the roundabout further around for clarity:

MK Roundabout 2

As you can see, the lane layout is a nice natural progression around the roundabout, with certain lanes being forced off at particular points, so as I said above, you choose roundabout lane 2 or 3 depending on how far around the roundabout you intend to go.


Whilst the above is based on the UK Highway Code, as brhans says in the comments, the green line makes no sense - you are forced back onto the motorway from whence you came...

The road markings on the approach to the roundabout modify the normal rules, and we end up with this:

MK Roundabout 3

The road markings never intend for you to choose the left hand lane on the roundabout, they intend for you to take either the middle or the right hand lane.

The left hand lane on the roundabout remains there for people who are already on the roundabout and are coming around to join the motor way in the direction you were travelling.

  • 4
    So ... the green line/lane is reserved for people who have accidentally left the M1 and want to rejoin it? Seems unlikely ...
    – brhans
    Oct 24, 2016 at 19:06
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    your answer is confusing, because the road signs do dictate the rules. It's people that don't read them and do what the first half of your answer says that cause accidents on roundabouts!
    – Alnitak
    Oct 25, 2016 at 0:06
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    A general comment. Never panic if you are in the right-hand lane on a roundabout and realize that you cannot safely move into the left-hand lane for your desired exit. People who force their way across lanes cause accidents and very many near-misses. It's a roundabout. Just go around it again, all 360 degrees. It'll be far easier the second time around, knowing the layout and signage better.
    – nigel222
    Oct 25, 2016 at 12:18
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    You should probably edit this answer to make it clearer. It looks like you have answered and then added an updated answer at the bottom. However your first part says "That's the only acceptable use of those lanes." and then at the end you give a different and in my view much more sensible answer of lane use.
    – Chris
    Oct 25, 2016 at 12:25
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    @Chris that's what I meant by confusing - you can't see "this is the only acceptable use" and then go on and say something completely different. The whole first half of this answer is irrelevant.
    – Alnitak
    Oct 25, 2016 at 16:42

The "correct answer" to the question should be on the road signs you have just passed as you approached the roundabout. They should have indicated which of the two lanes to choose for the various exits marked on the road (M1 southbound, MK (Milton Keynes?), and A509 southbound)

The road markings in your second picture are also directions for traffic that is already on the roundabout (coming from the right).

The "general principle" in the UK is that if you are going to pass several several exits before you leave (i.e. you are turning right and staying on the roundabout while you turn through 270 degrees) you enter in the inside lane, and "spiral outwards" to get into the correct lane to leave, as the other traffic exits from the outside lane(s).

There may be more than one lane leaving the roundabout at an exit, depending on the number of lanes on the road away from that exit. At major road junctions (which this one appears to be, from the pictures) the outside lane may only lead to the next exit - i.e. you can't (officially!) continue on the roundabout if you are in the outside lane.

Since the entrance to the roundabout is controlled by traffic lights, the "easiest" options will be to take the left and right hand lanes on the roundabout, not the central one - but if you are going to MK, you will probably need to move out of the right hand lane soon if you do that.


In this particular case I think the right lane should enter the rightmost of the three while the left should enter the center lane of the three.

This is the exit ramp from M1 south, so the only people wanting to get back on M1(S) will be those who've made a mistake. The two lanes on the exit ramp are signed for Milton Keynes, so both will want to enter a MK lane. The left lane should use the leftmost MK lane, the right lane the rightmost MK lane. The lane to M1(S) alone could be entered from the left lane but almost no one will want to do that.


Regardless of which lane you want to end up in on the roundabout, here's how I have always interpreted a junction like this:

Roundabout annotation

Whichever direction you're coming from, if you want to leave the path I've laid out by colour coding, you need to indicate and transfer.

So, if you wanted to take the A509(S), you'd:

  • approach the roundabout in the right-most lane
  • upon reaching the roundabout, continue into what is now the middle lane
  • find a safe moment to indicate then cross over into the right-most lane

I wish I had proof that this is correct (and I find that everybody seems to have their own idea about what to do, particularly on the M42 Northbound at Tamworth services — ugh), but it's what I do and it follows from the curvature of the roundabout's furniture.

  • Mind you, having found the junction on Google Maps (which is not actually the image in Thomas's answer, but has the same instructions painted on the tarmac) and having brushed up on my Highway Code, I'm getting less certain of this. Oct 24, 2016 at 18:31
  • See my answer :)
    – Moo
    Oct 24, 2016 at 18:33
  • 1
    In the UK you must use the right lane for any exit past 180 deg (if you assume your entry is 0 deg) on a roundabout, unless otherwise signposted (via sign or road markings) - and the right approach lane in this instance is signposted for straight on as well, so the right lane can be used for straight on traffic. The middle lane on the roundabout is also marked for a right turn, and if you follow this around, you will be politely forced off at the next exit past 180 deg. For subsequent exits past that one, you should take the right hand lane. Ive done that roundabout many a time.
    – Moo
    Oct 24, 2016 at 18:45
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    To me it looks as though your green & blue lines should be swapped over. Anyone already in the roundabout (blue lines) is probably wanting to exit to the M1 (left pair of lanes), while anyone entering the roundabout (green lines) is probably wanting to go to MK (right pair of lines). Since that intersection is controlled by traffic lights there won't be any traffic crossover.
    – brhans
    Oct 24, 2016 at 19:10
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    Yes, these lines are wrong. People coming off the M1(s) and not taking the A509(n) should take the middle or right lanes and stay in them until after the M1(s) exit slip. The exception is someone who didn't intend to come off the M1 at all, who should of course take the middle lane on the approach and then use the left land to rejoin. Conversely, people coming from the right on your picture (blue lines) in the left and right lanes taking the M1 should go to the left and middle lanes as they pass the A509(n) exit. Anyone on the A509(n) wanting to stay on it must use the left lane.
    – Alnitak
    Oct 25, 2016 at 0:13

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