A Red X displayed on overhead gantries or roadside gantries indicates that the lane directly below is closed to traffic.
Red X signals are heavily used on Smart Motorways to manage breakdowns, road accidents, debris, and maintenance work.
What this sign means
It is illegal to drive in a lane displayed under a Red X signal.
The signal protects stranded vehicles, breakdown operatives, emergency services, and road maintenance staff.
- Red X signal: Lane closed — strict legal prohibition.
- Flashing red lights: Mandatory requirement to stop or change lanes immediately.
- Camera enforcement: Automatic enforcement fine and points for passing a Red X.
What to do when you see it
Move out of the lane marked with a Red X as soon as it is safe to do so.
Do not wait until you reach the actual obstruction before merging into an open lane.
How this sign is tested
Theory tests check legal knowledge regarding the mandatory nature of Red X smart motorway signs.
Questions emphasise the penalty risks and extreme danger of ignoring lane closure signals.
Common mistakes
Continuing to drive down an empty Red X lane to bypass queuing traffic in open lanes.
Failing to move out of a Red X lane because no hazard is immediately visible ahead.
Test yourself on this one
Road and traffic signs is the biggest category in the question bank with 102 questions, and signs turn up inside other categories too. Work through them free, no sign-up needed.
Practise road sign questionsFrequently asked questions
What is the penalty for driving under a Red X?
Driving in a closed Red X lane carries an automatic £100 fine and 3 penalty points on your driving licence.
What if all lanes show a Red X?
If all overhead signals display a Red X, you must stop safely before reaching the gantry.
Are Red X gantries monitored by cameras?
Yes, gantry-mounted cameras automatically record vehicles that cross under illuminated Red X signs.