When it comes to driving on dual carriageways there are a few things you need to know before you take your test. A dual-carriageway is a multi-lane and usually high speed road with a central reservation/barrier separating the two carriageways.
There are three ways you will join a dual carriageway:
- Your road may simply turn into a dual carriageway ahead
- You may need to join via a slip road
- You may need to emerge directly onto a dual carriageway
How to emerge safely onto a dual carriageway...
Look out for signs stating that there is a dual carriageway ahead (left) and prepare for a possible and likely change in speed limit. Make sure you check your mirrors before changing your speed to one suitable for the new road.
Emerging from a slip road...
You need to take note of the speed limit that applies and use the slip road to build up to the speed of the traffic to your right to make it easier to join. If the dual carriageway isn’t very busy then most traffic will be travelling at the maximum speed. Look for a gap in the traffic and move into the left hand lane applying the mirror signal manoeuvre routine (M-S-M routine). You should always apply a right signal in good time before emerging. You should try and avoid looking too far over your shoulder when emerging, as regular mirror checks and a quick blind spot check will suffice in ensuring it is safe to join. Your aim should be to emerge without causing the traffic on the carriageway to alter their speed and/or direction.
Once you have joined the carriage way you should –
- Check your mirrors
- Cancel your right hand signal
- Keep in the left lane until you have had time to assess the traffic and conditions on the carriageway
- Make good progress
Emerging onto dual carriageway directly...
To turn left
Where there is no slip road you would need to emerge as you would to turn left onto a major road - take into account the speed limit on the dual carriageway to help judge a safe gap as traffic may be approaching very fast. Again, you must join where to do so would not cause other traffic them to change speed or direction.
To turn right
When joining a dual carriageway to take a right turn you will need to cross the first carriageway before you can join the carriageway you want. This is easiest where the central reservation is deep enough to have room to protect the full length of your vehicle to enable you to emerge from one carriageway at a time. Where there is not enough room you would need to be extra careful and turn right when both carriageways have a safe enough gap for you to drive across safely.
On the dual carriageway
Keep a safe following distance by applying the two second rule, and increase this in poor weather. You should stay in the left hand lane unless overtaking, allowing traffic to join carriageway or when turning right. To make good progress you should overtake slow moving traffic when you are sure you can do so safely.
When overtaking, assess the speed and position of the traffic behind you. When you are sure it is safe to do so make sure you follow the M-S-M routine and then keep to the same speed as the vehicle ahead.
You must look out for traffic that wants to join the carriageway so that you can be prepared to help them join. The main areas where you can expect traffic to join would be:
- As you approach slip roads
- Where there are junctions
- Out of garages
- Pulling out from parking areas
You will have three options to help traffic join:
- Moving out of the left lane
- Speeding up
- Slowing down
The best option is usually to move out of the left lane, so you should be checking your mirrors well before approaching the areas where traffic may want to join in order to be confident it is safe to switch lane.
When leaving the dual carriageway
On most carriageways you will get a sign for your exit giving you at least half a mile before the junction. Try to ensure you do not leave it too late to get into the left hand lane ready to exit.
These countdown markers are placed at 300yds (270m) - 200yds (180m) - 100yds (90m) up to your slip road for exit. You can use these as a guide for starting the M-S-M routine.
Look out for any signs that warn you of a sharp bend or change of direction to ensure you get your speed down in time and select the correct gear. Try not to slow down unnecessarily on the carriageway unless your mirrors show traffic is far away in the distance. Use the slip road to slow you speed down and be careful you do not travel too fast on the new road.
If you are learning to drive, the more you read up in preparation for your practical lesson, the smoother you will find it. You can contact us by email or phone to book your driving lessons with InTuition Driver Training.