The short answer: do not enter a yellow box junction unless you can see that your exit lane or road is clear. The main exception is a right turn: you may enter and wait in the box if oncoming traffic, or other vehicles waiting to turn right, are the only things preventing the turn.
That sounds straightforward until a queue starts moving, a light changes or the car ahead hesitates. The safest habit is to make the decision before the stop line: if there is not enough clear road beyond the box for your whole vehicle, wait behind it. A green signal is not an instruction to block the junction.
What the Highway Code says
Rule 174 of the Highway Code calls these criss-cross yellow markings box junctions. It says drivers must not enter until their exit road or lane is clear. The rule is backed by the Traffic Signs Regulations and General Directions 2016, so this is more than a courtesy to cross traffic.
It also sets out the important right-turn exception. You may move into the box and wait when you want to turn right and are stopped only by:
- oncoming traffic; or
- other vehicles that are themselves waiting to turn right.
At a signalled roundabout, the exception does not apply in the same way: you must not enter the box unless you can cross it completely without stopping.
The practical test before you move
Look past the far edge of the yellow markings, not merely at the car in front. Ask one question: if traffic stops now, is there a space beyond the box large enough for my vehicle? If the answer is no, stay where you are.
This matters even when traffic is creeping forward. A gap that only exists because the vehicle ahead is straddling the far side of the junction is not a reliable exit. Do not follow it into the box on hope that the queue will roll again.
When waiting in the box is allowed
The normal example is a driver turning right at a busy junction. The exit road may be clear, but an uninterrupted stream of oncoming traffic makes the turn impossible. In that situation, Rule 174 allows the driver to enter the box, wait safely, then complete the turn when there is a suitable gap.
The same can apply when another right-turning vehicle ahead is waiting for oncoming traffic. The key detail is why you are stopped. The exception is not a general permission to wait in a box because the road ahead is congested, because a pedestrian is crossing your destination road, or because you are trying to go straight on.
Three situations that cause most mistakes
Going straight ahead
There is no straight-ahead exception. If the far side is blocked, wait before the box, even if your traffic light is green and vehicles behind are impatient.
Turning left into a queue
A left turn does not get the right-turn exception. If vehicles on the road you are joining leave no room beyond the markings, do not enter. Wait for a genuine vehicle-length gap.
The light turns amber or red while you are waiting to turn right
Do not accelerate into a poor gap to escape the box. A driver who lawfully entered to turn right may need to complete the turn when it is safe, but must still give way as required and avoid creating a collision. The exact road layout, signal phase and movements of pedestrians and cyclists all matter. Rule 175 also requires drivers to stop behind the white stop line unless the light is green, subject to its limited amber-light exception.
Can a yellow box junction be enforced?
Yes. Box junction contraventions can be enforced by the relevant highway or traffic authority, including through camera evidence where that authority has the power to do so. Enforcement arrangements and the penalty process vary by location, so do not rely on a number quoted for a different council or city. If you receive a penalty charge notice, read the authority’s evidence, location details and appeal instructions carefully, and keep any relevant dashcam footage.
The better outcome is not needing to argue about a few seconds of footage. Make the call early and leave the yellow hatch clear when the exit is uncertain.
Do not confuse a box junction with a keep-clear marking
Yellow criss-cross lines at a junction are a box junction. Other yellow road markings, including areas marked to keep access clear, can have different rules and restrictions. Read the signs and road markings together rather than assuming every yellow grid works identically.
A calm approach in heavy traffic
- As you approach, scan the exit road or lane beyond the box.
- Allow for the full length of your vehicle, including the rear bumper.
- If going straight on or left, enter only when that space is already there.
- If turning right, enter and wait only when oncoming traffic or right-turning traffic is the sole reason you cannot finish the turn.
- At signalled roundabouts, wait unless you can clear the box in one movement.
Yellow box junctions reward patience, not opportunism. Waiting one signal cycle can feel slow, but it keeps cross traffic moving, protects vulnerable road users and avoids turning a routine journey into an enforcement problem.
Frequently asked questions
Can I enter a yellow box junction on a green light?
Only if your exit is clear enough for you to leave the box. A green light does not override the box-junction rule.
Can I stop in a yellow box if I am turning right?
Yes, but only where oncoming traffic, or vehicles waiting to turn right, are the only reasons you cannot complete the turn. This is not an exception for a blocked exit road.
What if traffic stops unexpectedly after I enter?
Each case turns on its facts. The sensible driving approach is to assess the exit before entering, leave a realistic margin and never deliberately follow a queue into the box. If a penalty notice arrives, check the evidence and the issuing authority’s appeal process.
This guide reflects the Highway Code and traffic-sign rules available on 28 September 2026. For the current official wording, check Rule 174 directly on GOV.UK.
