Joining and leaving a motorway

By the end of this topic you can

• You can use the slip road to build up speed and merge into a safe gap.
• You can give priority to traffic already on the motorway.
• You can plan your exit using junction numbers, advance signs and countdown markers.
• You can move into the left lane early and leave smoothly.
• You can check your speed after leaving and adjust to the new road.

What you need to know and understand

• You normally join a motorway from a slip road on the left or from an adjoining motorway.
• Give priority to traffic already on the motorway and adjust your speed to fit into a safe gap.
• You should not cross solid white lines separating lanes, for example at the end of the slip road.
• If the slip road continues as an extra lane, stay in that lane until you need to change.
• Countdown markers before an exit have three, two and one bars; each bar represents 100 yards to the exit.
• Learners may only drive on a motorway with an approved driving instructor in a car with dual controls.
• If you miss your exit, carry on to the next one; never reverse or cross the central reservation.

Joining: making the slip road work for you

Traffic on the motorway may move over to make room, but it does not have to. Never assume a driver will let you in. If no gap appears, ease off and use the remaining slip road to find one rather than forcing your way out.

1. As you enter the slip road, check your mirrors and look ahead to see how busy the motorway is.
2. Build up speed along the slip road so you are close to the speed of traffic in the left lane.
3. Signal right, check your right mirror and take a quick look over your right shoulder for a gap.
4. Adjust your speed, faster or slower, to fit smoothly into the gap.
5. Merge without crossing any solid white lines, cancel your signal and stay in the left lane while you settle.

Planning the exit

Know your junction number before you set off. Advance direction signs give you early warning, often a mile and then half a mile before the exit, followed by the countdown markers at 300, 200 and 100 yards. Move into the left lane in good time, ideally before the first sign if traffic allows.

Signal left in good time so drivers behind know your plan, then move onto the slip road and slow down there, not on the main carriageway.

Adjusting after you leave

After a spell at high speed, 50 mph can feel more like 30 mph, so check your speedometer rather than relying on how it feels. Slip roads often end at a roundabout or traffic lights, and some have sharp bends. Slow down early and be ready to stop.

Common mistakes

• Joining too slowly and making traffic brake. Use the whole slip road to build speed.
• Staring at the mirror and missing slowing traffic ahead. Keep alternating between ahead and your mirrors.
• Moving left at the last second. Get into the left lane well before your exit.
• Braking on the main carriageway before the slip road. Slow down once you are on the slip road.
• Misjudging speed after leaving. Glance at the speedometer as you approach the end of the slip road.

Test yourself: Joining and leaving a motorway

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

Go deeper

• Motorway Driving Tips for New Drivers