Junctions on Dual Carriageways
Dual Carriageways
Dual carriageways have lanes divided by a central reservation, sometimes with barriers.
They often resemble motorways but may contain slower traffic such as tractors or cyclists.
Emerging from a Side Road
Turning Left
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If no slip road exists, emerge as from a normal major road.
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If a slip road is provided:
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Use it to adjust speed and merge safely.
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Match your speed to the main traffic flow.
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Join only when it’s clear you won’t force others to slow or swerve.
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Remain in the left-hand lane until you’ve matched the general traffic speed.
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Turning Right
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You must first cross the near-side carriageway.
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Only proceed if the central reservation is deep enough to contain your vehicle safely.
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If it isn’t, wait until both carriageways are clear before crossing.
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Take extra care with long vehicles or trailers.
Defensive Driving Tip:
Motorcyclists can be hard to see and may be overtaking slower vehicles. Look twice before crossing or joining.
After Joining the Carriageway
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Check mirrors and cancel your signal.
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Stay in the left lane until you’re used to the flow.
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Accelerate smoothly to a safe speed.
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Watch for signs showing a new speed limit.
Leaving a Dual Carriageway
Turning Left
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If no slip road exists, follow the standard left-turn procedure.
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If there is a slip road:
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Use MSM/PSL early.
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Signal well in advance — speeds are higher.
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Reduce speed in good time.
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Turning Right
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Move into the right-hand lane early.
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Follow lane markings and signal clearly.
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Be extremely careful — you may need to cross multiple lanes of fast traffic.
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If in doubt, wait.