Once you know the national limits by road type, you can work out your ceiling almost anywhere. For a car: 30 in built-up areas, 60 on a single carriageway, 70 on a dual carriageway or motorway. Three numbers that cover most of your driving.
But here's the bit people forget: the limit belongs partly to the road and partly to your vehicle. A van, or a car towing a caravan or trailer, usually has lower limits than a solo car on the very same road — often 10 mph less on the open road.
And any number inside a red ring is a legal order, not advice. Whether it's a 20 outside a school or a 50 on a managed road, the red ring means that's the law, full stop.
The bits that matter
- Car national limits: 30 built-up, 60 single carriageway, 70 dual carriageway or motorway.
- Vans and anything towing usually have lower limits on the same road.
- A number in a red ring is a legal order — never just a suggestion.
Memory anchor
Sixty single, seventy dual
For a solo car on the open road, two numbers do most of the work: sixty single, seventy dual. One carriageway, sixty; two separated carriageways, seventy. Say it as a pair and it sticks.
Out on the road
Towing the family caravan
Same dual carriageway you usually do 70 on — but today there's a caravan on the back. Now your limit is lower, because towing changes the numbers. The road hasn't changed; your vehicle has. Knowing that keeps you legal when the setup changes.
The mistake everyone makes
Assuming the limit is the same for every vehicle
It's easy to think "70 on a dual carriageway" applies to everyone. It doesn't. Drive a van or tow a trailer and your limit on that same road is usually lower. The sign sets the road's maximum; your vehicle decides yours within it.