My route to and fro the school where I teach involves several roundabouts. Therefore, I should know the correct lane discipline for a roundabout. Here is a good article on the topic:
Roundabouts
Why Roundabouts Exist
This diagram shows the problem of having two busy roads
meeting without the presence of a roundabout. The red car is finding it
difficult to turn into the road on its
right. (This may also lead to holding up traffic behind).
Cars emerging on to the main road will also find it difficult to make progress when the road is busy.
This diagram shows the benefit of having a roundabout.
Now the roundabout rules apply people only need to give way
to the right allowing traffic to flow much more freely. The red car that
was finding it difficult before can now go
around the roundabout to turn right. The yellow car will now
find it easier to emerge as the vehicles on the right will be blocked
by traffic crossing their path.
Rules that apply
- Follow the M-S-M routine on approach ensuring you position in the appropriate lane in good time
- Give way to traffic that will cross your path from your
right. (You must not cause traffic on your right to change speed or
direction)
- Keep in correct lane on the roundabout
- Apply the M-S-M routine on your exit
The following diagrams show various roundabouts which will help explain how to deal with them and which lane to take.
Lane discipline
On a standard roundabout:
Turning left (red car)
Use the left lane as it is your first exit, signal left on approach.
Turning right (Exit 3 on diagram)
Signal right on approach and use the right hand lane and
stay on the inside of the roundabout until you pass the last exit that
is just before your turn (Exit 2 on diagram).
Check mirrors and signal left to confirm your intentions to
exit the roundabout.
Following the road ahead
On a standard roundabout (as blue car on diagram) you
should use the left lane and stay on the outside of the roundabout. No
signal will be required on approach as it is the
second exit you require, check your mirrors and apply a left
signal as you pass Exit 1.
Following the road ahead
If the layout was as below:
Approach on the right and stay on the inside of the
roundabout until you pass the first exit, then apply the M-S-M routine
for leaving the roundabout (giving a left signal).
Look for lane markings
If you are following the road ahead on a main route (eg dual
carriageway) you can often go ahead in either lane. If you approach on
the left then you should stay to the left in
new road, if you take the right hand lane on approach stay
on the inside of the roundabout and exit in the right hand lane in new
road.
Following the road ahead
If the layout was as below:
Approach on the left and stay on the outside of the
roundabout. As the exit you are taking (blue car) is your first then you
can indicate left on approach to confirm your
intentions.
Turning Right
If you are turning right (yellow car) use the right hand
lane and stay on the inside of the roundabout until you pass the first
exit. Then check your mirrors and apply a left
signal.
Giving Way
Although traffic can come all the way around the
roundabout from Exit 1 (ahead) you will mainly have traffic to give way
to only coming out of one exit - Exit 2 that intends to
turn right therefore the majority of the time they will need
to approach in their right hand lane, the traffic approaching on their
left should be turning left and if so you will
not need to give way.
Looking for Lane Markings
If the lane markings show that you can use either lane
following the road ahead: If you approach on the left then you should
stay to the left in new road, if you take the right
hand lane on approach stay on the inside of the roundabout
and exit in the right hand lane in new road.
Lane Discipline
On this roundabout the road markings show that the left
hand lane should only be used for turning left. This will normally be
where the left exit is more of a main route (i.e.
city centre route or leading to a motorway).
Following the road ahead (where the left-hand lane is for turning left only)
As the markings show - you will need to use the right
hand lane to follow the road ahead. Keep to the inside of the roundabout
until passing the first exit. Be extra careful
until passing the first exit and as you exit in case other
vehicles have followed the road ahead in the left lane, which is the
case on most roundabouts.
Following the road ahead on a dual carriageway
Lane discipline
Here you will be able to follow the road ahead in either lane.
If you approach in the left hand lane stay on the outside of the roundabout and keep to the left on your exit.
Key Considerations
- Ensure you approach in the correct lane in good time
- Most dual carriageways are high speed roads - try to keep appropriate speed
- Be mindful of traffic to your sides especially larger vehicles which may not stick to their lane
Multi lanes
If you have three or more lanes - look for road markings for most appropriate lane to use.
Roundabouts - Making Progress
Take opportunities to make progress when traffic to your
right will be blocked - here the yellow car can emerge as the traffic
opposite, which is going ahead at the roundabout,
is blocking the traffic to the right.
On this example the yellow car can take the opportunity to
make progress when the blue car turning right blocks the traffic.
When the roundabout is big enough to allow enough room - if
you are turning left (yellow car) and you can see traffic intends to
turn right then you will not cause them
to change speed or direction as you will be on the outside
of the roundabout and they would be on the inside.
When vehicles are coming around the roundabout and you have
not seen which junction they emerged from, you will not know which exit
they are taking so will need to give way to
them.
Mini Roundabouts
When dealing with a mini roundabout the rules are just the
same as a standard roundabout where you need to give way to traffic
crossing your path from the right.
(Because junctions are closer it is easy to give way to
traffic you have priority over). Follow the M-S-M routine on approach.
Sometimes mini roundabouts are hard to identify early:- look out for the sign.
Example for taking a right turn
Priority
Here the yellow car has priority as traffic must give way to their right.
Key Points
- When turning right ensure your signal is maintained (re-apply if it cancels) otherwise traffic may not give way to you.
- Drive around the centre circle (large vehicles may have no choice but to drive over it).
- When following the M-S-M routine on exit your left
signal showing your intentions to leave roundabout will not always be
important - apply if you have time. When turning
right your steering will take priority.
