National speed limit UK: understanding the rules
A fool-proof guide to the UK’s national speed limit
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By Ben Welham
Last updated: 13 May 2025
Wrapping your head around the national speed limit rules is something you begin to do from a young age as you peer at your parents’ speedometer from the back seat.
But it’s only when you start driving yourself that you realise what it actually all means, and which roads have which limits.
In this guide, we’re going to give you a detailed overview of the national speed limit rules in the UK, where they apply, how you know the speed and other important driving tips related to it.
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What is the national speed limit?
The national speed limit refers to the default legal speed limit that applies to a road when there are no specific road signs to say otherwise.
These limits are set by law, and different speeds apply to different types of roads and even the type of vehicle you’re driving.
If the limits are broken, you can face fines, driving licence points and even some more severe punishments.
When does the national speed limit apply?
The national speed limit applies to three main types of road:
Single carriageways
Dual carriageways (and motorways)
Built-up areas (towns, villages, etc)
All of these roads have different national speed limits you need to stick to, which we’ll get into the details of below.
What is the national speed limit sign?
The standard national speed limit sign is a white circle with a black diagonal line across it.
When you see this sign, you can increase your speed – if safe to do so – to the national speed limit on that particular bit of road.
Blue national speed limit sign
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Sometimes, you’ll see a light blue circular sign with a white number in the middle. This denotes the minimum speed for that road.
For example, if you see one with a large white ‘30’ on it, then you know the minimum speed is 30mph.
When you see the same sign but with a diagonal red line across it, you know that’s now the end of the minimum speed limit on that road.
The national speed limit on dual carriageways
Dual carriageways have a maximum speed limit of 70mph for most vehicles, including cars, motorcycles, dual-purpose vehicles (i.e. pickup trucks) and car-based vans.
However, this is lowered to 60mph for HGVs (heavy goods vehicles) over 7.5 tonnes, cars towing caravans or trailers, buses (coaches and minibuses included) and vans (not car-derived versions).
A dual carriageway can be denoted by a central barrier separating the traffic going in either direction.
But if you are on a motorway with variable speed check signs, make sure to keep an eye on them as they may change quickly to ease congestion further up the road.
The national speed limit on single carriageways
Single carriageways have a maximum speed limit of 60mph for cars, motorcycles, dual-purpose vehicles (i.e. pickup trucks) and car-based vans.
The speed limit is 50mph for cars towing caravans or trailers, vans (not car-derived versions), buses (coaches and minibuses included) and lorries over 7.5 tonnes.
In built-up areas
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When driving in built-up areas (i.e. towns) in England, the speed limit is 30mph unless marked otherwise.
In Wales, the speed limit is 20mph unless stated otherwise. Note that the same can apply in England’s built-up areas if a road sign states it (commonly seen near schools and residential areas).
Speed cameras in these areas also tend to be more prevalent, to ensure the safety of pedestrians and cyclists.
What is a built-up area?
A built-up area can be identified in a few different ways:
Streetlights at regular intervals (roughly every 180 metres)
Residential homes
Towns and town centres
Villages
Urban roads
The national speed limit for a car-towing trailer
In the UK, the national speed limit for towing a trailer or caravan is less than it is for regular cars.
Single carriageways – 50mph
Dual carriageways – 60mph
Motorways – 60mph
Built-up areas – 30mph (same as all other vehicles)
There are also some additional rules for towing you need to know:
You must not tow in the outside (right-hand) lane of a three-lane motorway, unless all other lanes are closed
You need to have proper working brakes and lights
The towing setup must be road legal and safe
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Speed limit, not target
The speed limit is the absolute maximum and does not mean it’s safe to drive at that speed all of the time.
Driving at speeds too fast for the road and traffic conditions is dangerous.
You should always reduce your speed when:
Road layouts or conditions change, such as when approaching bends
Sharing the road with pedestrians, cyclists and horse riders
Poor weather conditions present themselves
Driving at night when it’s more difficult to see other road users
More information for new drivers
If you’re new to driving, all of these rules can seem really overwhelming and hard to digest, but we’re here to make it all make sense.
We have a range of helpful new driver guides to make sure you’re ready to tackle the open road with confidence.
The first step now is to buy your first car. Looking for a used hatchback? You’ve come to the right place.
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