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Dual Carriageways

Dual carriageways are roads with two or more lanes of traffic travelling in each direction. The outer or right-hand lane in each direction is the lane nearest to the centre of the dual carriageway.

You must normally drive in the left-hand lane of a dual carriageway. You may use the outer lane of a two-lane or three-lane dual carriageway only:

  • for overtaking, and
  • when intending to turn right a short distance ahead.
  • Drive as close as you safely can to the left-hand edge of the approach road.
  • Watch for oncoming traffic.
  • Take the turn when it is safe to do so.
  • Keep to the left-hand lane on the dual carriageway and build up your speed to that of the normal flow of traffic subject to the speed limits and road conditions.
Maximum Speed on a dual carriageways
National speed limits stands at 70mph with a central reservation otherwise it would be 60mph unless speed limit signs are in place 

Crossing a dual carriageway or joining it by turning right

  • Wait in the median space (the gap in the central dividing strip) until there is a safe gap in traffic.
  • Finish your crossing or turn into the second half of the dual carriageway and build up your speed to that of the normal flow of traffic, subject to speed limits and prevailing road conditions.

If another vehicle is already blocking the median space, wait on the minor road until there is enough space to clear the first half of the road without stopping on the carriageway. If the median is too narrow for your vehicle, wait on the minor road until you can clear both sides of the carriageway, or complete your turn in one go.

When driving a large vehicle, it is not safe to treat each half of the dual carriageway as a separate road. You should remain on the minor road until you can cross both sides of the dual carriageway without having to stop.

Always take care when you are behind large vehicles or vehicles towing trailers when they are turning. Remember, a long vehicle or combination needs extra room to finish a turn. Cyclists, motorcyclists and pedestrians, in particular, should be extra careful when near these vehicles.

Turning right from a dual carriageway

  • Follow the normal procedure (see below) and move into the right-hand lane. If there is a deceleration lane, move into it.
  • At the junction, turn into the median space and wait for a safe gap in traffic.
  • When it is safe to do so, finish your turn and move into the left-hand lane of the road you are entering.