Dual carriageways

By the end of this topic you can

• You can join a dual carriageway and build up to the speed of traffic.
• You can keep to the left lane and use the right lane correctly.
• You can change lanes safely at higher speeds.
• You can cross or turn right across a dual carriageway using the central reserve gap safely.
• You can plan your exit early.

What you need to know and understand

• Keep to the left lane; use the right lane only to overtake or to turn right a short distance ahead.
• Overtake on the right. Do not overtake from the left lane when traffic is moving at normal speed.
• Before crossing, check that the central reserve gap can hold your whole car clear of both carriageways.
• Obey the signed speed limit; it is a maximum, not a target.
• Any vehicle towing a trailer or caravan is limited to 80 km/h.
• Learner permit holders may use dual carriageways that are not motorways.
• Leave at least a two-second gap, and more in wet weather.

Joining and leaving

Where there is a slip road or acceleration lane, use it to match the speed of traffic in the left lane before you merge. Signal right, check your mirror and right blind spot, and give way to traffic already on the road. Where you join from a side road without a slip road, wait for a gap big enough to build up speed without forcing anyone to brake.

To leave, look for the exit signs early, move into the left lane in good time, signal left and slow down in the deceleration lane rather than on the main carriageway.

Lane use and changing lanes

At higher speeds, gaps close quickly. Check mirrors early and look over your shoulder before every lane change. Signal, then move over gradually and give way to anyone already in the lane. Once you have overtaken, return to the left lane when it is safe, without cutting in.

Crossing the central reserve

Turning right onto or across a dual carriageway is one of the riskiest moves you will make as a learner.

1. Check that the gap in the central reserve is long enough for your whole car.
2. If it is, and it is empty, cross the first half when clear and wait in the gap.
3. Cross the second half, or join the far side, when that carriageway is clear.
4. If the gap is too short or already occupied, wait on the side road until you can do the whole move without any part of the car in a live lane.

Common mistakes

• Sitting in the right lane after overtaking.
• Merging too slowly from a slip road and forcing traffic to brake.
• Changing lanes without a shoulder check.
• Waiting in a central gap that is too short, leaving the back of the car in a live lane.
• Braking on the main carriageway before reaching the exit lane.

Test yourself: Dual carriageways

Answer each question, then read the explanation. Questions come in a random order each time.