Single Carriageway Speed Limits in the UK
Single carriageways -- roads without a physical central reservation -- carry a national speed limit of 60 mph for cars, but significantly lower limits apply to vans and HGVs.
Speed Limits by Vehicle Type
| Vehicle Type | Speed Limit | Notes |
|---|---|---|
| Cars & motorcycles | 60 mph | National speed limit |
| Vans (up to 3.5 tonnes) | 50 mph | 10 mph lower than cars |
| Towing caravan/trailer | 50 mph | Same as vans |
| HGV (over 7.5 tonnes) | 40 mph | Includes articulated vehicles |
| Buses & coaches | 50 mph | All sizes |
Understanding Single Carriageway Speed Limits
Single carriageways make up the vast majority of the UK road network. They range from quiet rural B-roads to busy A-roads carrying thousands of vehicles per day. What defines a single carriageway is simple: the two directions of traffic are not separated by a physical central reservation. If there is only a painted line -- even double white lines -- between you and oncoming traffic, you are on a single carriageway.
The national speed limit on single carriageways is 60 mph for cars and motorcycles. This is indicated by the white circular sign with a diagonal black stripe. Many drivers assume this sign always means 70 mph, but on a single carriageway it means 60 mph. Misunderstanding this distinction is one of the most common causes of inadvertent speeding on A-roads.
For vans and vehicles towing trailers, the limit drops to 50 mph on single carriageways. This 10 mph reduction from the car limit is frequently overlooked, particularly by van drivers who may be accustomed to driving at the same speed as surrounding car traffic. HGVs over 7.5 tonnes face the most restrictive limit at just 40 mph, reflecting the greater stopping distances and collision severity associated with large goods vehicles.
Single carriageways are statistically the most dangerous road type in the UK. Despite carrying less traffic than motorways, they account for a disproportionate share of fatal and serious collisions. Head-on collisions are the primary risk, occurring when vehicles cross the centre line while overtaking, drifting, or losing control. The 60 mph limit on these roads has been debated; some safety campaigners advocate reducing it to 50 mph to match the van limit.
Speed enforcement on single carriageways includes fixed cameras at known hotspots, mobile camera vans positioned in lay-bys, and handheld speed guns operated by police officers. Average-speed cameras are increasingly used on longer stretches of A-road, particularly those that have been upgraded with improved surfaces and junctions but retain single carriageway geometry.
Many single carriageways pass through villages and towns where lower local speed limits apply. It is common to encounter transitions from 60 mph to 30 mph or 40 mph with little warning beyond the speed limit sign. Being alert for these changes is essential to avoid unintentional speeding, particularly in areas where cameras are positioned at the entry to lower speed zones.
Key Facts
Car Limit
60 mph
Van / Towing
50 mph
HGV Limit
40 mph
Frequently Asked Questions
What is the speed limit on a single carriageway?
The national speed limit on a single carriageway is 60 mph for cars and motorcycles. Vans and vehicles towing trailers are limited to 50 mph, and HGVs over 7.5 tonnes to 40 mph.
What is the difference between a single and dual carriageway?
A single carriageway has no physical central reservation separating opposing traffic. If the road only has painted white lines (even double white lines) separating traffic, it is a single carriageway. A dual carriageway has a physical barrier such as grass, concrete, or metal.
Are all A-roads single carriageways?
No. Many A-roads are dual carriageways and carry a 70 mph national speed limit for cars. The designation (A-road, B-road) indicates importance, not construction type. Always check whether there is a physical central reservation to determine the correct speed limit.