The DTC
Essential Skills7 min read

Speed Limits & Choosing a Safe Speed

Speed limits are maximums, not targets. The examiner is watching whether you adjust your speed to the road, the weather, and the traffic around you.

The full guide

Speed limits set the maximum legal speed for a road, but they do not mean it is always safe to drive at that speed. The examiner is assessing whether you choose an appropriate speed for the conditions — and whether you know the limits for different roads and vehicles.

In built-up areas with street lighting, the limit is 30 mph unless signs show otherwise. On single carriageways it is 60 mph for cars. On dual carriageways and motorways it is 70 mph. These are the national speed limits and you must know them without relying on signs.

However, the limit is not the target. In wet weather, your stopping distance doubles. In fog or at night, you must reduce your speed to match your reduced visibility. Near schools, shops, and residential areas, even 30 mph may be too fast for the conditions. The examiner wants to see you read the road and adjust accordingly.

Know your stopping distances. At 30 mph in dry conditions it takes 23 metres to stop — about six car lengths. At 50 mph it takes 53 metres. In wet conditions, these distances roughly double. Keeping a safe separation distance from the vehicle in front gives you time to react and stop safely.

Common faults

  • Driving too fast for the road or weather conditions
  • Not knowing the national speed limits for different road types
  • Driving below the speed limit when conditions allow normal progress
  • Following the vehicle in front too closely
  • Not reducing speed in poor weather or low visibility
  • Speeding in a 20 mph zone near schools or residential areas
  • Accelerating too aggressively away from junctions or roundabouts

What the examiner looks for

  • You know and observe the correct speed limits for each road type
  • You adjust your speed to match road, weather, and traffic conditions
  • You maintain a safe separation distance from the vehicle ahead
  • You do not hold up traffic by driving unnecessarily slowly
  • You accelerate smoothly and progressively to appropriate speeds
  • You reduce speed before hazards rather than reacting at the last moment

Quick tips

  1. 1Street lights mean 30 unless signs say otherwise — memorise this rule
  2. 2If it is wet, leave at least a four-second gap to the car in front
  3. 3Reduce speed before a bend — you cannot see what is around the corner
  4. 4In 20 mph zones, stick to 20 — these are areas with high pedestrian risk
  5. 5Use the limit as a maximum, not a target — conditions often demand less

Common questions about speed limits & choosing a safe speed

What are the national speed limits?
For cars: 30 mph in built-up areas, 60 mph on single carriageways, 70 mph on dual carriageways and motorways. These apply unless signs show a different limit.
Can I be marked down for driving too slowly?
Yes. If you drive significantly below the speed limit on a clear, safe road without reason, the examiner may mark it as a fault. You should make normal progress while staying within the limit.
How do I judge stopping distances?
Use the two-second rule in dry conditions — when the car in front passes a fixed point, you should not pass it before counting two seconds. In wet conditions, double this to four seconds.
What if I cannot see a speed limit sign?
Use the presence of street lighting as your guide. Regularly spaced street lights indicate a 30 mph limit unless another limit is signed. No street lights and no signs means national speed limit applies.
Should I slow down for every bend?
You should reduce speed before bends where you cannot see the full road ahead. The sharper the bend and the more limited your view, the more you should slow down before entering it.
Can I fail for exceeding the speed limit?
Yes — speeding is a serious fault. Even briefly exceeding the limit by a small amount can result in a fail. Always stay within the posted limit and adjust down for conditions.

Ready to put this into practice?

These guides are a great starting point, but nothing replaces working with a DVSA-approved instructor who can give you real-time feedback.

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Speed Limits & Choosing a Safe Speed | The DTC