This sign is often mounted on a lamp post or a small post at the start of a stretch of road, especially where a lower limit has just ended.
It does not state a number. Instead it tells you that the default national limit for that type of road now applies, and it is up to you to know what that limit is for your vehicle.
What this sign means
The plate is a plain white circle with a black diagonal band running from top left to bottom right. It marks the point where any previous lower speed limit ends and the national speed limit for that road begins.
The actual limit depends on the road type and your vehicle. For cars and motorcycles it is 30mph in built up areas, 60mph on single carriageways, and 70mph on dual carriageways and motorways. Larger vehicles, and vehicles towing, have lower limits on some of these roads.
What to do when you see it
You need to judge which limit applies based on the road layout and what you are driving or towing.
- Check whether you are on a single or dual carriageway
- Remember your vehicle's specific limit, especially if towing a trailer or caravan
- Adjust speed gradually and only once it is safe to do so
- Watch for street lighting, which usually indicates a 30mph limit even without a sign
How this sign is tested
The theory test regularly asks candidates to identify this sign and to state the correct limits for cars, motorcycles, and towing vehicles on different road types.
Questions may also test whether you understand that street lighting overrides the plate in the absence of other signs, implying a 30mph limit.
Common mistakes
A common error is assuming the national limit is always 70mph, forgetting that it varies by road type and vehicle class.
Learners also sometimes fail to recognise that this sign gives no fixed number, wrongly believing it always means the maximum motorway speed applies.
Test yourself on this one
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Practise road sign questionsFrequently asked questions
What does the national speed limit sign look like?
It is a white circle with a black diagonal stripe from the top left to the bottom right, usually mounted on a small post.
What speed does it allow for cars?
It permits up to 60mph on single carriageways and 70mph on dual carriageways and motorways, unless a lower limit applies to your vehicle.
Does it apply to vehicles towing trailers?
No. Vehicles towing trailers or caravans have lower national limits than solo cars, typically 50mph on single carriageways and 60mph on dual carriageways.