Speed and speed limits

By the end of this topic you can

• You can work out the speed limit on any road from the signs and street lighting.
• You can keep to the limit without staring at the speedometer.
• You can choose a lower speed when the road, weather or traffic calls for it.
• You can explain why the limit is a maximum and not a target.

What you need to know and understand

• National limits for cars and motorcycles in Great Britain: 60 mph on single carriageways, 70 mph on dual carriageways and motorways (Highway Code rule 124).
• Roads with street lights usually have a 30 mph limit in England and Scotland and a 20 mph limit in Wales, unless signs show otherwise (rule 124).
• Local limits can also apply, such as 20 mph in some built-up areas of England and Scotland, 30 mph on some lit roads in Wales, or 50 mph on single carriageways with known hazards (rule 124).
• Cars towing a caravan or trailer have lower limits: 50 mph on single carriageways and 60 mph on dual carriageways and motorways (rule 124).
• The limit is the absolute maximum. It does not mean that speed is safe in every condition (rule 125).
• You should always slow down for bends, bad weather, darkness, and when sharing the road with pedestrians, cyclists, horse riders and motorcyclists (rule 125).
• Speeding can bring a fine and penalty points. New drivers who reach 6 points within 2 years of passing lose their licence (Highway Code annex 5).

Reading the limit from the road

A red circle with a number gives the limit. A white circle with a black diagonal stripe means the national speed limit applies, so for a car that is 60 mph on a single carriageway and 70 mph on a dual carriageway or motorway.

Small repeater signs remind you of the limit along the road. If you see street lights and no repeater signs, assume 30 mph in England and Scotland, or 20 mph in Wales. A 20 mph zone has an entry sign and an end sign, and may also have traffic calming.

• Built-up area with street lights: 30 mph (20 mph in Wales) unless signed otherwise
• Single carriageway, national limit: 60 mph
• Dual carriageway, national limit: 70 mph
• Motorway: 70 mph, or lower if variable limit signs show it

Why the safe speed is often lower

Your stopping distance grows quickly as speed rises. The Highway Code's typical figures show a car needs about 23 metres to stop from 30 mph in good conditions, but about 96 metres from 70 mph. In the wet it can be at least double.

A good rule is to drive at a speed that lets you stop well within the distance you can see to be clear (rule 126). On a narrow lane with a blind bend, that might be far below 60 mph.

Keeping to the limit without staring at the dial

Glance at the speedometer briefly, then look back at the road. Use the right gear for your speed, because it helps the car hold a steady pace. On downhill stretches, choose a lower gear early so the engine helps control your speed (rule 160).

When you pass a sign for a lower limit, you should already be at the new speed as you reach it. Plan ahead and ease off in good time rather than braking hard at the sign.

Common mistakes

• Treating the limit as a target. Ask yourself what speed would let you stop in the space you can see.
• Missing the end of a lower limit and crawling along well below it. Look for signs and keep up with safe progress.
• Assuming a lit road in Wales is 30 mph. The default there is 20 mph, although some roads are signed at 30 mph.
• Speeding up downhill without noticing. Pick a lower gear before the slope.
• Slowing down only at the sign. Lose speed smoothly before you reach it.

Test yourself: Speed and speed limits

Answer each question, then read the explanation. Questions come in a random order each time.

Go deeper

• UK Speed Limits for Cars