When dealing with slower vehicles in front of you, try to anticipate the need to overtake and act early to avoid having to reduce your speed. Use the MSM routine to overtake safely.
Early use of mirrors is essential. Even when not preparing to overtake, you should be regularly checking your mirrors, so you always know what is happening behind you.
Before overtaking, make sure there is space in the lane to your right. You should be able to move into the lane without affecting other road users. Be certain there is nothing hiding in your blindspot.
As always, signal if necessary. Other road users may not anticipate you overtaking, so a right signal just before pulling out is a good idea.
Even if there are no other road users behind you, a signal can be given for the benefit the road user you are about to overtake, who make see it in their mirrors.
A small amount of steering to the right will take you swiftly and smoothly into the right lane.
Cancel your signal as soon as you have changed lanes.
Accelerate if necessary to pass the vehicle(s) you are overtaking, making sure to stay at a sensible speed for the conditions and within the speed limit.
Again, use the MSM routine to pull in safely. In normal conditions, when you can see the last vehicle you passed in your rearview (centre) mirror, this is a good indication that there is enough space to move back to the left lane.
As you are pulling away from this vehicle, you should not be affecting them when moving back to the left so a signal may not be necessary. Some motorists prefer to give a left signal at his point anyway, just in case. This is ok, but try to avoid giving a misleading signal, for example if you are about to pass an exit on the left.
Once you have checked it is safe, and having signalled if necessary, ease back into the left lane.
Cancel your signal as soon as it has served its purpose.
Other road users joining from the left
Sometimes, other road users will be joining the dual carriageway from the left, either via a slip road or a normal left turn. In these situations, consider whether you can make it easier for them (and safer) by moving to the right lane.
Only move to the right lane if it is safe to do so, and use the same procedure as for overtaking.
If it is not safe to change lanes, stay where you are and adjust your speed as necessary to help others merge safely.
Good use of planning and anticipation skills in these situations will help keep things as smooth and safe as possible.Get animated examples with the interactive Dual Carriageways app for iPad