How to drive on dual carriageway

Joining a dual carriageway or motorway – what to do

On the approach to joining a dual carriageway, you will have an acceleration lane. It’s important that you adjust your speed (usually by going faster) so you fit in smoothly with the traffic already on the road. Remember, it’s their priority so you shouldn’t force your way onto the dual carriageway or motorway by forcing other vehicles to slow down or change direction for you.

Apply the MSPSL routine early on the approach

Check your interior and right door mirrors as a minimum and apply a signal if it is safe. You may want to wait to put your signal on if someone is passing you on your right side.

Look at the road markings on the approach, if there are no road markings, keep left and increase your speed so you fit in with the current speed of the cars passing you. You should look over your shoulder (blind spot check) before joining the dual carriageway. If nobody is there, then join the dual carriageway gradually.

If a vehicle is beside you, consider coming off the gas and joining behind them. If it’s a slow moving lorry then if it’s possible, consider increasing your speed and go in front of them. Once you have joined the dual carriageway, recheck your mirrors and cancel your signal.

Joining a dual carriageway

Leaving a dual carriageway or motorway – what to do

Firstly, look out for road signs and road markings in good time, so you are not rushing or doing a dangerous manoeuvre to avoid missing your exit.

If you are late seeing signs, don’t do anything dangerous, just to come off at the next exit. Look out for the 1 mile away signs and 0.5 mile away signs which will help you decide when to get in the left hand lane to prepare leaving. Try to avoid overtaking on the approach to leaving a dual carriageway or motorway.

Apply the MSPSL routine to come off

Mirrors: Before the 300-yard marker
Signal: Inline with or just after the 300-yard marker
Position: Keep in the left hand lane
Speed: Don’t slow down too much until you leave the dual carriageway and join the slip road.
Look: Look ahead onto the slip road for hazards/junctions and act accordingly.

Once you have left the dual carriageway, recheck your mirror/s and cancel your signal. Usually there is a junction ahead such as a roundabout, so look our for signs or traffic lights, and start planning your approach to the junction.

Leaving a dual carriageway

On the dual carriageway or motorway – what to do

Fatal accidents usually happen on fast roads. The biggest accident type on UK roads is a rear end shunt. So be sure to keep enough clearance between you and the car in front.

The 2-second rule

Pick a landmark in front of you, like a bridge. If the car in front of you gets to the bridge before you have counted 2 seconds, then you are following too close.

Say to yourself, “only a fool breaks the 2-second rule.” This takes 2 seconds to say.

In the rain, the 2-second rule doubles to 4 seconds and in the ice and snow, the 2-second rule increases up to 10 times (20 seconds).

Lane discipline

It’s obviously important to stay in your lane at all times, unless overtaking. Be aware of other road users – many are doing long journeys and if they’re tired, they may switch off and their vehicle position may drift. Look out for this at all times.

When you are passing high vehicles such as lorries, try to overtake swiftly so you are not in their blind spot for too long. In high winds, the lorries may drift slightly which is another reason why you don’t want to be stuck in their blind spots for too long.


Always keep to the left hand lane, unless you are overtaking. If you decide to overtake a vehicle, make sure you come back over to the left hand lane when possible. By doing this it will reduce overall congestion on the dual carriageways and motorways.

Hard Shoulder

The Hard Shoulder is for emergencies only, unless road signs state you can use it. In the event you have an accident or your car breaks down, try to position your vehicle on the harder shoulder (as far to the left as possible). Always exit the vehicle and face the oncoming traffic, away from your car, so if someone hits your car, you are well out of the way.