Interactive tool · October 2026
MSMPSL at a T-junction
Watch a real car turn left or right at a T-junction: mirror, signal, mirror again, position, speed and look. Try a closed junction, where hedges hide the road you are joining, and an open one with a clear view both ways. 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 in 3rd gear and turns left or right at a T-junction with a Yield sign. Choose the turn, a closed junction, where hedges hide the road you are joining, or an open one with a clear view both ways, and whether that road is clear or a car is coming from the right. Press play to watch it in real time, or tap any letter to see that step on its own.
Turning
The junction
The road you are joining
Slow motion and step by step run at half speed. Step by step stops after every step: tap Next or press →.
Steering: early or late turn
white car
grey car
This is a teaching diagram. It shows each step on its own so you can see it clearly, and the distances may not match a real junction one to one. As your skill grows, each step takes less time and some of them overlap: you can be changing your speed and your position while you are already looking. The order stays the same: mirror, signal, mirror, position, speed, look.
Section 2
The routine, step by step
Six steps, always in the same order. Each one sets up the next: you check behind before you tell anyone your plan, you tell them before you move over or slow down, and you arrive slowly enough to look properly.
Mirrors
Interior mirror first, then the door mirror on the side you are turning to. Who is behind you and how close? Turning left: is a cyclist or motorcyclist coming up on your left? Turning right: is anyone about to overtake you?
RSA: use your mirrors before signalling, slowing down or turning (Rules of the Road p. 44); check them well in advance for traffic following behind you (pp. 129 and 131).
Signal
Indicator on, in good time, so the driver behind knows why you are about to move over and slow down. A signal tells others your plan; it does not give you right of way.
RSA: give a left-turn signal (p. 131) or a right turn signal (p. 129); signalling does not give you the right of way (p. 55).
Mirror again
A second look in the same door mirror. Has your signal changed anything behind you? Is anyone still coming up beside you?
RSA: the Mirror, Signal, Mirror, Manoeuvre (MSMM) routine, Essential Driver Training session 3.
Position
How we teach itTurning left: about 70 cm from the left kerb, about the width of a door. As the kerb starts to curve, follow it round at the same distance: you start turning earlier and more gently, need less steering, and do not swing wide.
Turning right: about 30 cm from the centre line, about the width of your mirror, leaving room for others to pass on your left.
RSA: turning left, do not swing wide (p. 131); turning right, take up a position just left of the middle of the road and, where possible, leave room for others to pass on the left (p. 129).
Speed
How we teach itBrake early and gently. How slow depends on how much you can see: about 5 km/h and 1st gear at a closed junction, about 15 to 20 km/h and 2nd gear at an open one. The gear must suit your speed and the situation, and keep the car responsive.
RSA: at a Yield sign you must slow down, but you only have to stop if you need to let traffic pass (p. 126).
Look
How we teach itStart looking about 3 to 4 car lengths before the junction: right, left and right again, and keep looking as the view opens up. At a closed junction it only opens in the last metre or so. We break the look into four parts: LADA.
RSA: traffic already on the road you are joining has right of way (p. 127). Stop, look, listen, and look again (p. 128).
Closed or open: how slow, which gear
The routine is the same at every junction. What changes is how much you can see, and so how much speed you take off.
| Closed junction | Open junction | |
|---|---|---|
| What you can see | Hedges, walls or parked cars hide the road you are joining until you are almost at the line | A clear view both ways from well back |
| Speed at the line | About 5 km/h, creeping | About 15 to 20 km/h |
| Gear | 3rd to 1st | 3rd to 2nd |
Our teaching, not RSA figures. Whatever the junction, the gear must suit your speed and the situation, and keep the car responsive.
It happens faster than you think. Press play in real time: at 50 km/h the mirrors, signal and second mirror check are over in a few seconds. That is why we practise the routine until it runs on its own, and why the long, slow part is the look at the end.
Section 3
The look, broken down: LADA
Look, Assess, Decide, Act. It is how we teach the last step, so that looking turns into a decision instead of a glance. Switch the simulator to Car from the right to see a “wait” decision, and to a closed junction to see how little you can see until you reach the line.
Look
Right first: on the near side of the road you are joining, traffic comes from your right. Then left, then right again. Turning right, you cross the traffic from the right and join the traffic from the left, so you need a gap both ways.
Assess
What is coming, how fast and how far away? Is anyone crossing the mouth of the junction? Cyclists and motorcyclists are small and easy to miss.
RSA: bicycles, e-scooters, mopeds and motorcycles can be difficult to see because of their small size (p. 128); give way to pedestrians and cyclists crossing the junction before you turn (p. 131).
Decide
Go or wait. If something would reach you while you are still turning, wait for it to pass.
RSA: at a T-junction, traffic on the road ending at the junction must wait for traffic already on the other road to pass (p. 127).
Act
Go smoothly in the gear you chose, follow the kerb round and finish on the left-hand side of the new road. Or wait at the line, ready to go, and look again before you move.
Once you are on the new road, check the left mirror and then the right to confirm your position: your distance from the kerb and from the centre line.
Turning right, start the turn as soon as the front of the car enters the new road. A sooner turn, when possible, needs less steering, so there is less to straighten up and less work, and it allows a higher speed and better progress.
RSA: finish your turn so that you enter the left-hand side of the road you are joining (pp. 129 and 131); turning right, wait until the road is clear in both directions (p. 129).
Section 4
Where the routine comes from
MSMPSL joins two routines the RSA already uses. What is the RSA's and what is our own teaching is marked below.
- Mirror, Signal, Mirror, Manoeuvre (MSMM). The RSA's Essential Driver Training covers it in session 3: by the end of that session you should be able to carry out the MSMM routine correctly. EDT Learner Driver Information Booklet, version 2, April 2019.
- Position, Speed, Looking (PSL). The RSA's Driving Instructor's Handbook (third edition, 2019) uses PSL alongside observations, signals and manoeuvres in its sample motorcycle (IBT) lesson, and gives MSMM as an example of a memory aid that makes routines easier to remember.
- Turning left. Rules of the Road (2026), turning left from a minor road onto a major road: check your mirrors well in advance, give a left-turn signal and slow down; at a Stop or Yield sign, wait at the entrance until the road is clear; finish the turn on the left-hand side of the new road; do not swing wide; give way to pedestrians and cyclists crossing before you turn (p. 131).
- Turning right. Rules of the Road (2026), turning right from a minor road onto a major road: check your mirrors well in advance and give a right turn signal; take up a position just left of the middle of the road; at a Stop or Yield sign, wait at the entrance until the road is clear in both directions; where possible, leave room for others to pass on the left; when a safe gap occurs in traffic from both directions, finish the turn on the left-hand side of the road you are joining (p. 129).
- Our own teaching, not RSA figures: about 70 cm from the kerb turning left (a door's width) and about 30 cm from the centre line turning right (a mirror's width); about 5 km/h and 3rd to 1st at a closed junction, about 15 to 20 km/h and 3rd to 2nd at an open one; starting the look 3 to 4 car lengths out; and breaking the look into LADA. The distances where each step happens in the simulator are a teaching example, not a rule: with experience the steps get quicker and some overlap, but the order stays the same.
Section 5
Common questions
Do I have to stop at a Yield sign?
No. At a Yield sign or Yield line you must slow down, but you only have to stop if you need to let traffic pass. At a Stop sign or Stop line it is different: you must stop every time, even if there is no traffic on the road you are joining (Rules of the Road p. 126).
Why look right first?
Because the nearest traffic comes from your right. Traffic keeps left in Ireland, so on the near side of the road you are joining it is heading towards you from the right, and it has right of way (p. 127). Turning left you join it; turning right you cross it. Then look left, for traffic from that side and for anyone crossing, and right again before you go. Turning right, you need the road clear in both directions (p. 129).
Is MSMPSL an official RSA routine?
Not under that name. The RSA's EDT course teaches Mirror, Signal, Mirror, Manoeuvre (MSMM), and the RSA's Driving Instructor's Handbook uses Position, Speed, Looking (PSL). MSMPSL puts the two together: the “manoeuvre” is broken down into position, speed and look.
What is a closed junction?
One where hedges, walls or parked cars hide the road you are joining until you are almost at the line. In the simulator the shaded area is what the driver can actually see past the hedges. In our drawing, from 4 car lengths out you can see only about 9 metres of the road to the right; from the line, about 50 metres; and the full view only once the front of the car is level with the edge of the road you are joining. That is why you creep up slowly in 1st, ready to stop.
Why follow the curve of the kerb when turning left?
Because it lets you start the turn gently, as the kerb starts to curve, instead of all at once at the line. Turn left in the simulator to compare. The white car follows the kerb round at about 70 cm; the grey car behind keeps straight until its front reaches the edge of the road it is joining, then turns. To finish in the same place, the grey car needs about 1.3 turns of the steering wheel instead of 0.9 (93% of full lock instead of 66%), it has to go round a little slower, and even then its front swings a few centimetres over the centre line.
Why start a right turn early?
Because a sooner turn, when possible, needs less steering: less to straighten up afterwards, less work, and it allows a higher speed and better progress. Turn right in the simulator to compare. The white car starts turning as soon as its front enters the new road; the grey car behind waits until its front is just short of the centre line. In our drawing the late turn needs about 1.2 turns of the steering wheel instead of 0.86 (88% of full lock instead of 62%), so about 2.4 turns to wind on and back off instead of 1.7. That is with our Corolla's steering: 1.38 turns from straight ahead to full lock. More steering takes more time, so the grey car has to go round a little slower: at the open junction about 12 km/h instead of 15 km/h for the same sideways force, and even then its driver has to turn the wheel faster. Its front corner also passes about 19 cm from the far kerb instead of 48 cm.
An early turn still must not cut the corner: you finish on the left-hand side of the road you are joining (p. 129).
Which gear should I be in?
It depends on the junction. At a closed junction, where you creep up at about 5 km/h, change from 3rd to 1st. At an open junction, where about 15 to 20 km/h is enough, change from 3rd to 2nd. Either way, the gear must suit your speed and the situation, and keep the car responsive. In an automatic the car picks the gear and you control the speed with the brake.
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. The turn is worked out from its real wheelbase (2.64 m): the car follows the curve of the kerb, keeping about 70 cm from it all the way round, and finishes in the left-hand lane of the new road. With the 5 m kerb radius in the drawing, that needs about 22 degrees on the front wheels; turning at the last moment instead would need more steering and a tighter turn. Turning right, the car starts to steer once its front is about a metre past the line and finishes in the left-hand lane of the road it joins, without cutting the corner. The Yield line, the Yield triangle on the road and the upright Yield sign are the markings the Rules of the Road describes for a Yield junction (p. 74).
Want to drill junctions with an instructor?
We build the routine on quiet roads first, then on busier junctions, until it runs on its own and your attention is free for the look.
Book a lessonThe 70 cm and 30 cm, the speeds and gears for closed and open junctions, the 3 to 4 car lengths and LADA are Smart Driving Academy's teaching, not RSA figures. Educational tool only. It does not replace the Rules of the Road or qualified instruction.
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