Interactive tool · October 2026
MSMPSL at a roundabout
Watch a real car come up to a roundabout from 6 o’clock and take the first, second, third or fourth exit: mirrors, signal, position, speed and look. Try a roundabout with one lane each way, then one with two. Play it in real time, or tap a step to see it on its own.
Section 1
Try it yourself
A Toyota Corolla drives up a 50 km/h road towards a roundabout with Yield markings. Choose one lane or two lanes each way, and the exit. Press play to watch it in real time, use slow motion or the slider, or tap any step to jump to it. The roundabout is clear: no other traffic yet.
Roundabout
Exit
1st exit: turning left
This is a teaching diagram. The distances where each step happens are an example, not a rule: with experience the steps get quicker and some of them overlap, but the order stays the same. The roundabouts are drawn by us to a realistic size; the RSA does not give dimensions. One lane each way: roads 8 m wide, roundabout 32 m across, ring 7 m.Two lanes each way: roads 14 m wide (3.5 m lanes), roundabout 48 m across, ring 9 m with two lanes.
Section 2
The rules: think of a clock
The RSA’s golden rule works on almost any roundabout, whatever the number of exits. Picture the roundabout as a clock, with the road you are on at 6 o’clock.
The golden rule
For any exit from 6 o’clock to 12 o’clock, generally approach in the left-hand lane. For any exit from 12 o’clock to 6 o’clock, generally approach in the right-hand lane. If road markings show which lane to use, follow them.
RSA: Rules of the Road p. 135.
Treat it as a junction
Yield to traffic coming from your right and to traffic already on the roundabout, but keep moving if the way is clear. Move into the correct lane in good time.
RSA: p. 136. At a Yield line you must slow down, but you only have to stop if you need to let traffic pass (p. 126).
First exit, turning left
Approach in the left-hand lane, signal left as you approach, and keep signalling until you have taken the left exit.
RSA: p. 136.
Straight ahead
Approach in the left-hand lane, unless road markings say otherwise. Do not signal left until you have passed the exit before the one you want.
RSA: p. 137.
Later exits, 12 to 6 o’clock
Approach in the right-hand lane, unless road markings say otherwise, and signal right. Keep the right signal on until you have passed the exit before yours, then change to the left signal, move over towards the left and keep signalling left to leave.
RSA: p. 137.
At every exit
Take extra care when you leave, checking for cyclists and motorcyclists who may be carrying on round. Watch out for pedestrians crossing the approach and exit roads, long vehicles that need a different course, and cyclists who may stay in the left-hand lane and signal right to go on round.
RSA: pp. 137–138.
Section 3
How we teach it
The RSA tells you which lane and which signal. These are the habits we add on lessons; they are our own teaching, not RSA figures, and the simulator follows them.
- A mirror before every signal. Check the mirror before you signal, change lanes, slow down or turn (RSA: Rules of the Road p. 44; the test looks for mirrors used in good time and before signalling, p. 36).
- Signal about 30 to 40 metres before the roundabout. Our rule of thumb: if you can see the other drivers, they can see you, so that is the time to show your signal.
- The left mirror going on and coming off. Always a look in the left mirror just before you go onto the roundabout and again just before you come off it.
- Where to be, one lane each way. First exit: favour the left of your lane and follow the kerb round. Straight ahead: the middle of the lane and the middle of the roundabout. Third and fourth exit: favour the right of your lane, then the inside of the roundabout near the island.
- When to change the signal. Straight ahead: left signal once the bonnet is just past the middle of the road before your exit. Third and fourth exit: just past the middle of that road, left mirror, then change from the right signal to the left and start moving out (halfway to your exit on a one-lane roundabout; from that road on a two-lane one, in one smooth curve into the left-hand lane of the exit road).
- Changing lanes: mirror and side window. Moving right, the right mirror and then a look out of the right window; moving left, the left mirror and the left window. Not over the shoulder. In the two-lane drawing the car for the third and fourth exit starts in the left-hand lane and changes lanes as the Position step.
- Speed and the first exit. About 20 km/h at the Yield line when the way is clear. After the first exit, straight into the middle of the lane, then the left and right mirrors to confirm your position.
Section 4
Common questions
Do I have to stop at the Yield line?
No. Treat the roundabout as a junction: yield to traffic coming from your right or already on the roundabout, but keep moving if the way is clear (Rules of the Road p. 136). At a Yield line you must slow down, but you only have to stop if you need to let traffic pass (p. 126).
Which lane do I use to go straight ahead?
The left-hand lane, unless road markings say otherwise. Where traffic conditions call for it, for example a long line of traffic in the left lane signalling left, or roadworks in the left lane, the RSA allows a different course (Rules of the Road p. 137). Road markings always come first.
When do I signal left going straight ahead?
Not on the approach. Signal left only once you have passed the exit before the one you want (Rules of the Road p. 137). In the simulator that is the 9 o’clock road: as the bonnet passes the middle of it, mirror, then signal left.
Why look at 12 o’clock and then to the right?
Traffic goes round clockwise, so the cars you have to yield to come from your right, and cars already on the roundabout have priority (Rules of the Road p. 136). A look across to 12 o’clock first shows you what is coming round towards your right; the look to the right then shows what is about to reach your entry.
What do the road markings at the entry mean?
The broken white Yield line, the white Yield triangle on the road and the upright Yield sign all mean the same thing: give way to traffic on the road ahead, which here is the roundabout (Rules of the Road pp. 70 and 74).
What is the car in the picture?
A Toyota Corolla Hatchback, drawn to its real size (4.37 m long, 1.79 m wide), driving on the left as in Ireland. Its line is checked against the drawing so that no part of the car leaves the road.
Want to practise roundabouts with an instructor?
We start on quiet roundabouts with one lane, then move on to busy two-lane ones, until the routine runs on its own and your attention is free for the traffic.
Book a lessonThe positions (favouring the left or the right of the lane), the signal distance, the speed, the extra mirror checks, the mirror-and-window check for changing lanes and where the car moves out are Smart Driving Academy's teaching, not RSA figures. The roundabouts are our own drawings. Educational tool only. It does not replace the Rules of the Road or qualified instruction.
See also: MSMPSL at a T-junction