Dual Carriageways
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What is a dual carriageway?
A dual carriageway is a multi-lane road that uses a central reservation to separate traffic travelling in different directions. Most dual carriageways have two or three lanes, with the right-hand lane dedicated to overtaking and turning right. While the left-hand lane is used for normal travel. You will be made aware of the start of the dual carriage by the sign below.
The central reservation on the dual carriageway
Central Reservation on a Dual Carriageway
The central reservation separates traffic travelling in opposite directions and it can be made from different materials. Some central reservations are grass verges, some have large concrete crash barriers, while on roads that have been converted from a single carriageway into a dual one, the central reservation could be steel ropes attached to posts in the ground. The central reservation stops traffic from turning around in the road and travelling in the other direction, as it is very easy to misjudge the speed of oncoming traffic on a dual carriageway. There are often breaks in the central reservation to allow for traffic leaving and joining the central reservation, if you are attempting to exit at one of these points, ensure the length of your vehicle can fit in the gap if you intend on waiting within the gap for an opening. If your vehicle can’t fit in the gap, wait for a suitable break in traffic to drive straight through it.
Dual Carriageway Ahead Sign
The speed limit on the dual carriageway
The speed limit on the dual carriageway is 70mph, however, there are some restrictions based on the type of vehicle you are driving and whether or not the carriageway is in a built-up area. Dual carriageways in urban areas often have a lower speed limit, usually between 30-40mph depending on how built up the area is, while cars and vans towing trailers also have a lower speed limit too. The speed limit on the dual carriageway is as follows;
- Cars, motorcycles and small vans: 70mph
- Cars and vans towing a trailer: 60mph
- Buses and coaches up to 12 metres in length: 60mph
- Large goods vehicles up to 12 tonnes in weight: 60mph
- Large goods vehicles over 12 tonnes in weight: 50mph
Dealing with cyclists on a dual carriageway
Cyclists are permitted by the Highway Code to travel on this particular type of road, however, as a motorist you should be extremely careful when passing a cyclist on this type of road. Cyclists will rarely travel faster than 20mph, so you have less time to react when trying to avoid a collision. When passing a cyclist make sure there is enough room for you and them, give them ample room as they may swerve and ensure you take precautions as you pass by.
Joining the dual carriageway
Joining a dual carriageway is something that many learner drivers find difficult due to the speeds at which traffic is moving at. As most vehicles will be travelling at the national speed limit, you need to build up speed on the slip road, wait for a suitable gap in traffic to your right and join the carriageway when it is safe to do so. The slip road is used to build up speed, however you need to be mindful of the length of each as some are shorter than others. In situations where the slip road is much smaller, you need to wait for a larger gap before you merge, as this will allow you to build up speed while on the carriageway. As you travel along the slip road, keep looking to the right for a suitable gap and once you spot one, be confident about entering your desired point.
Overtaking on the dual carriageway
If there is more than one lane on dual carriageway you are travelling on, the right hand lane is used for overtaking. When you wish to pass another vehicle you should use the MSM driving routine to look for potential hazards before making your pass. When travelling in the left hand lane, check your interior mirror and right door mirror, looking out for fast approaching, vehicles and motorcycles. When it is safe to move into the right-hand lane, apply a signal while taking a look in your right door mirror for any motorists you may have missed. Once the road is clear move over to the right hand lane, pick up speed to pass the vehicle on your left, then use the MSM driving routine to move back into the left hand lane once you have built up a reasonable gap. Check your interior and left door mirror, apply a signal while checking your mirrors again, then move over to the left hand lane once it is safe to do so.
Exiting the dual carriageway
To exit the dual carriageway use the MSM driving routine to move over to the left hand lane in good time, do not cross any chevron hatch markings as you join the slip road and look out for countdown markers which have up to 3 stripes on a green background, with each stripe representing 100 yards. As you approach the deceleration lane, start to gradually slow down to take your exit and check your mirrors on the new road to update your information.
Tips to help you stay safe on dual carriageways
These driven test tips will help keep you and other road users around you safe when you’re travelling on a dual carriageway.
Steer subtly
When driving at high speeds small movements in the steering can result in large changes in direction. When changing lanes a small amount of steering is all that is needed.
Use the MSM routine
You need to be aware of your surroundings at all times. Use the mirror signal manoeuvre routine when you slow down, change lanes or overtake another vehicle. Use the routine to check for hazards before you change lanes or direction.
Drive cautiously in adverse weather
When visibility is reduced and the conditions on the road are poor, give extra room to vehicles around you and travel at a slower speed, as it takes longer to stop in rain or snow. Use your fog lights when necessary and be mindful of the road conditions you face.
