Box junctions are marked with criss-cross yellow lines painted across the road surface, usually at busy intersections, traffic lights, or station exits.
Their primary purpose is to ensure traffic flows freely by preventing vehicles from blocking junctions.
What this sign means
The golden rule of box junctions is that you must not enter the box unless your exit road is clear.
Blocking a box junction causes gridlock and is enforced by traffic cameras and local council penalty fines.
- Yellow criss-cross lines: Keep junction clear.
- Right-turn exemption: You may enter and wait if turning right and only oncoming traffic or other turning vehicles prevent completion.
What to do when you see it
Check that your exit space is clear before driving into the box. If traffic ahead is queued, wait behind the entrance edge of the box.
When turning right, you can enter the box and wait inside as long as your exit road is clear of stationary vehicles.
How this sign is tested
Theory tests frequently check candidates on the exact exception regarding turning right at box junctions.
On practical tests, entering a box junction and getting stuck due to queued exit traffic will cause an automatic serious fault.
Common mistakes
Following the vehicle ahead into the box without checking if there is room for your vehicle beyond the box.
Failing to realise that you are allowed to wait inside the box when turning right if oncoming traffic is holding you up.
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Practise road sign questionsFrequently asked questions
Can I enter a box junction when turning right?
Yes, if your exit road is clear and you are prevented from turning only by oncoming traffic or other vehicles waiting to turn right.
What happens if I stop in a box junction?
Stopping inside a box junction due to queuing exit traffic can incur a fine and will cause a practical driving test failure.
Are box junctions enforced by cameras?
Yes, many box junctions are camera-enforced and trigger automatic Penalty Charge Notices (PCNs) for infractions.