What Speed Limit Am I On? How to Know Your Current Limit on UK Roads
The speed limit on any UK road depends on road type and posted signs. Lit roads default to 30 mph. Single carriageways to 60 mph. Motorways and dual carriageways to 70 mph. Lower limits are always shown by signs. When towing a caravan or trailer, lower limits apply on faster roads.
Many UK drivers are uncertain about the speed limit on a given road — particularly where no signs are visible. The rules are straightforward once understood, but they have some important nuances that are not widely known.
How do UK speed limits work?
UK speed limits are set by road type and environment. For most roads, a default limit applies without any posted signage. When a local authority or Highways England sets a different limit, it is always shown by signs at the zone entry point and by repeater signs along the road.
| Road type | Default limit (cars) | How you know |
|---|---|---|
| Built-up area with street lighting | 30 mph | Lamp posts — no speed sign needed |
| Single carriageway (no lighting) | 60 mph | National speed limit sign, or no signs after leaving a lit area |
| Dual carriageway | 70 mph | National speed limit sign |
| Motorway | 70 mph | National speed limit sign, or no overhead gantry limit displayed |
What does the national speed limit sign mean?
The national speed limit sign — a white circle with a diagonal black line — does not mean 70 mph on every road. It means the national speed limit applicable to that road type applies:
- On a single carriageway: 60 mph
- On a dual carriageway: 70 mph
- On a motorway: 70 mph
This is one of the most commonly misunderstood elements of UK speed limits. Drivers who treat the national speed limit sign as meaning "70 everywhere" risk significantly exceeding the limit on single-carriageway A-roads where the limit is 60.
How street lighting indicates a 30 mph zone
Under UK regulations, a road with street lighting — lamp posts no more than 200 metres apart — has a default speed limit of 30 mph, regardless of whether any speed limit signs are present. No signs are required to make 30 mph legally enforceable on a lit road.
This means that if you are driving on a road with lamp posts and no posted signs, you are in a 30 mph zone. This catches many drivers out, particularly on wider lit roads that feel like they should carry a higher limit.
💡 Key rule: If there are lamp posts, assume 30 mph unless a sign explicitly says otherwise. A wide lit road with no signs is still 30 mph.
When signs override default limits
Any posted sign overrides the default limit. Common examples:
- 20 mph zones: increasingly common in towns and residential areas; always signed at the zone entry and with repeaters
- 40 and 50 mph limits: common on A-roads at the edge of built-up areas, or on dual carriageways with junctions
- Variable speed limits: smart motorways use electronic overhead gantries to set limits of 60, 50, or 40 mph — these are legally enforceable when a limit is displayed
- Roadworks limits: temporary limits at roadworks are legally enforceable when accompanied by the mandatory signage
Do speed limits differ for vans, caravans, and larger vehicles?
Yes. The standard limits above apply to cars and motorcycles. Different limits apply to vehicles when towing, and to larger goods vehicles and minibuses.
| Vehicle type | Built-up area | Single carriageway | Dual carriageway | Motorway |
|---|---|---|---|---|
| Car / motorcycle | 30 mph | 60 mph | 70 mph | 70 mph |
| Car towing caravan or trailer | 30 mph | 50 mph | 60 mph | 60 mph |
| Goods vehicle ≤7.5 tonnes | 30 mph | 50 mph | 60 mph | 70 mph |
| Goods vehicle >7.5 tonnes | 30 mph | 50 mph | 60 mph | 60 mph |
| Minibus (9–16 passengers) | 30 mph | 50 mph | 60 mph | 70 mph |
⚠️ If you are towing: lower limits apply on faster roads. A car towing a caravan is limited to 60 mph on motorways and dual carriageways, and 50 mph on single carriageways — even where a higher limit is posted. Speed Angel is designed for standard car use and does not automatically apply towing limits.
How to always know the speed limit in real time
Even with the rules above understood, knowing the precise limit on a specific road in real time requires either active observation of signs or a GPS-based speed limit tool.
Navigation apps (Google Maps, Waze) include a speed limit indicator, though coverage varies. Dedicated speed limit awareness apps provide a focused, prominent real-time display of the current posted limit — and alert you the moment your GPS speed exceeds it.
Speed Angel shows the current posted speed limit for the road you are on and alerts you in real time if you exceed it. It works in the background alongside any navigation app, without requiring you to look at the screen.
Frequently asked questions
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The default limits apply. In a built-up area with street lighting (lamp posts no more than 200 metres apart), the limit is 30 mph even without signs. On an unlit single carriageway with no posted limit, it is 60 mph. On a dual carriageway or motorway with no posted limit, it is 70 mph.
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Cars towing are limited to 50 mph on single carriageways and 60 mph on dual carriageways and motorways. The 30 mph limit in built-up areas is unchanged. These lower limits apply even where a higher limit is posted — the posted limit sets the maximum and towing rules restrict you further below it.
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Most modern navigation apps and sat navs include a speed limit display, but coverage and accuracy vary by road type and region. Dedicated speed limit awareness apps focus specifically on real-time limit display and tend to provide more reliable, prominent feedback — including an audio alert when you exceed the limit.
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A 20 mph zone is a posted speed limit area, typically in residential streets, town centres, or near schools. It is indicated by a 20 in a red circle at the zone entrance and repeater signs along the road. Unlike 30 mph zones in lit areas, 20 mph zones are always explicitly signed — there is no default 20 mph limit.
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Yes. A single road can pass through multiple speed limit zones — for example, a rural A-road dropping from 60 to 40 as it approaches a village, then to 30 through the village, then back to 60. Each change is marked by a sign at the transition point and by repeater signs along the zone. Always look for signs at junctions, when entering towns and villages, and when passing schools or roadworks.
Always know the limit — without looking at signs
Speed Angel shows the current posted speed limit for the road you are on and alerts you the moment you exceed it. No need to rely on sign detection alone. Free 14-day trial on Android.
▶ Download Speed Angel FreeDisclaimer: Speed limits and regulations are subject to change. Always observe posted signs, which take precedence over any database or app. Speed Angel is a driving awareness aid — it does not replace your legal obligation to observe posted speed limits, including temporary limits at roadworks.