Knowing the correct speed limits – and when to slow down – is one of the most vital parts of safe driving. The legal speed is the maximum allowed, not necessarily what’s safe in all conditions. Below is a thorough guide for learners.
📏 National Speed Limits for Cars & Motorcycles
According to the GOV.UK:
- In built-up areas with street lighting (unless signs show otherwise): 30 mph (or 20 mph in Wales)
- On single carriageway roads: 60 mph (the “national speed limit” for that road type)
- On dual carriageways: 70 mph (if no lower limit signs)
- On motorways: 70 mph for most cars & motorcycles, unless signs limit you further
These are defaults; always obey posted signs if they differ.
🏷 Lower Limits & Special Cases
- If there is a signposted limit (e.g. 40, 50, 20 mph zones), that overrides the national limits on that stretch of road.
- In Wales, many built-up areas now default to 20 mph, even where previously 30 mph applied.
- When towing a caravan or trailer, or driving certain types of vehicles (vans, heavier motorhomes), the permitted maximum speeds may be lower than for cars.
🧠 Instructor Tips & Real-World Advice
- Never assume “national speed limit = safe speed” – always adjust based on road, weather, visibility and traffic.
- Always look for signs as you enter new zones; speed limit changes are often after junctions.
- On dual carriageways, especially, it’s common to see a national speed sign – once you pass it, that’s your limit until you see a new sign.
- Use your mirrors and scanning so that when a speed drop is approaching (roundabouts, houses, junctions), you slow early rather than brake hard.
⚠ Common Mistakes Learners Make
| Mistake | Consequence | Prevention |
|---|---|---|
| Assuming the motorway limit still applies when variable limits are active | Loss of control, increased collision risk | Always reduce speed when roads are wet, foggy, or visibility low |
| Not noticing repeater signs | Driving at the national limit when conditions are poor | Keep eyes moving and look for speed reminder signs |
| You may exceed the signed speed on smart motorways | Know your vehicle class (van, motorhome, towing) and its limits | On smart motorways, the overhead signs are binding |
| Overlooking speed limits for different vehicle types | You may exceed the signed speed limit on smart motorways | You may be breaking the law even if you’re under the “car” limit |
📋 Speed Awareness Checklist
- Identify the default speed for road type (built-up/single/dual / motorway)
- Check for posted speed limit signs (signed changes)
- Adjust speed for conditions (weather, curves, traffic)
- Observe for upcoming speed changes (junctions, entrance to town)
- Know your vehicle’s specific limits (car, van, towing)
- Use smooth acceleration and braking to approach/lower speed zones
❓ FAQs
Q: What does the “national speed limit” sign mean?
A: It means you can travel at the default national speed for that road type (e.g. 60 mph on single carriageway, 70 mph on dual/motorway) until the next sign.
Q: Can I exceed the speed limit a little?
A: No. The posted limit is absolute. Police may show some discretion (especially for small overspeed in certain cases), but legally you are committing an offence if you exceed the limit.
Q: What about driving in poor weather?
A: The speed limit does not change with the weather. You must drive below the limit if conditions demand.
Q: Are there minimum speed limits?
A: Rarely. Some roads (e.g. tunnels or special roads) might have minimum speed signage, but in general, no broad minimum limit applies.
📚 Attribution & Official Sources
This page draws on rules from The Highway Code and the official GOV.UK “Speed limits” guidance (which lists national speed limits per road type). Additional data from RAC, Motoring Research, and Adrian Flux help with real-life applied examples.
