Junctions

Taking the first exit at a roundabout using a filter lane

A filter lane sets your route, not your right of way - the lane markings decide where you're going, but the same observation and speed judgement still apply.

Core skill Step-by-step lesson Common mistakes

This video has no narration. Follow the written steps below.

Practical test

Why it matters

Examiners are watching whether you treat the give-way point where the filter lane rejoins as a genuine junction, not a formality - misreading it as automatic priority is exactly the kind of mistake this skill is testing.

What to look out for

Filter lane means route, not priority

The lane tells you where the road goes. Where it rejoins is a give-way point - you must give way to traffic already there, the same as joining from any side road.

Commit early, hold the line

Once you've chosen the filter lane, keep the steering smooth and avoid drifting toward the main roundabout lane.

Key steps

  1. 1 Identify the filter lane from the lane markings and layout of the roundabout itself, not from signs - many mini-roundabouts have no advance sign for a filter lane at all, so the marking on the road is what tells you it's there.
  2. 2 Check mirrors and signal left - Rule 186 requires a left signal on approach for a first exit, filter lane or not - then move into the lane in good time rather than cutting across at the last moment.
  3. 3 Keep your speed low enough to judge pedestrians, cyclists, and traffic from the right, even though the filter lane feels like a more direct route.
  4. 4 Treat the point where the filter lane rejoins the road as a junction: there's a give-way marking there, and Rule 172 means you MUST give way to traffic already on the roundabout or exit road before you continue - only build speed once you've actually given way and the road is clear.

Common mistakes

Treating the filter lane as automatic priority

The filter lane sets your route, not your right of way. Where it rejoins the road is a give-way point like any other junction - you MUST give way to traffic already there, not just check and continue.

Assuming a sign will tell you when to move over

Many mini-roundabouts have no advance sign for a filter lane - read the lane markings on the road itself and get into position in good time, rather than waiting for a sign that might not come or cutting across at the last moment.

Carrying too much speed through the filter

Keep the car slow enough to respond if the lane narrows, a crossing appears, or traffic ahead slows unexpectedly.

Example scenarios

Illustrative, AI-generated examples - not real photographs.

Avoid
Missing the filter lane and joining the roundabout itself to take the first exit - the filter lane lets you take this exit without joining the roundabout's circulation, but you still need to give way to pedestrians, cyclists, and any crossing traffic within it.
Do
Using the filter lane correctly - reading the layout early, signalling left in good time, moving into the lane without cutting across at the last moment, then giving way to traffic with priority rather than treating the filter as a free run through.

Highway Code

This lesson is a revision aid, not a replacement for The Highway Code.

Rule 184

On approach, use Mirror-Signal-Manoeuvre at all stages, decide as early as possible which exit you need, give an appropriate signal (see Rule 186), and time your signals so as not to confuse other road users.

Read Rule 184 on GOV.UK

Rule 186

Unless signs or markings indicate otherwise, choose your lane and signal by your exit: first exit - signal left and approach in the left lane; going ahead - no signal on approach, then signal left after the exit before yours; right or full circle - signal right and approach in the right lane, then signal left after the exit before yours.

Read Rule 186 on GOV.UK

Rule 172

The approach to a junction may have a 'Give Way' sign or a triangle marked on the road. You MUST give way to traffic on the main road when emerging from a junction with broken white lines across the road.

Read Rule 172 on GOV.UK

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