Turning right in a yellow box junction: what the Highway Code actually says

Quick answer

• You MUST NOT enter a box junction until your exit road or lane is clear. That is a legal requirement, not advice.
• There is one exception: you may enter and wait when you are turning right and only oncoming traffic, or other vehicles waiting to turn right, are stopping you.
• Your exit still has to be clear. The exception covers being blocked by oncoming traffic - not by a queue on the road you are turning into.
• At signalled roundabouts the exception does not apply: you MUST NOT enter unless you can cross the box completely without stopping.

Watch

Turning right in a yellow box junction

Box junctions catch people out because the headline rule and the exception pull in opposite directions, and most drivers only ever learn the headline. The result is one of two errors: sitting back and blocking the traffic behind you when you were entitled to move forward, or edging in when you were not.

When should you wait at a green light?

A green light means you may go if the way is clear - not that you must. Rule 176 puts the condition plainly: only go forward on green if there is room for you to clear the junction safely, or you are taking up position to turn right. So you wait at a green light when moving forward would leave you stranded in the junction, and you wait when you are turning right and oncoming traffic has not given you a gap yet.

Painting a box on that junction does not change the answer - it makes it enforceable. Which is where rule 174 comes in.

The box junction rule, and the one exception

The Highway Code uses MUST NOT for rule 174, which means it is backed by law rather than being good practice: you must not enter the box until your exit road or lane is clear. Then it adds the exception in the same rule - you may enter the box and wait when you want to turn right, and are only stopped from doing so by oncoming traffic, or by other vehicles waiting to turn right.

• Turning right, blocked only by oncoming traffic: you may enter and wait.
• Turning right, but the road you are turning into is queued: you may not - your exit is not clear.
• Going straight ahead or turning left with anything blocking your exit: you may not enter, no exception applies.
• At a signalled roundabout: you may not enter unless you can cross the whole box without stopping.

This is worth getting right beyond the test. Rule 174 is one of the Highway Code's MUST NOTs, so legislation sits behind it - and where a council has taken on moving-traffic enforcement, entering a box junction you were not entitled to enter can bring a penalty charge notice through the post. The exception is a genuine defence when it applies, and no defence at all when it does not.