Frequently Asked Questions

20mph Speed Limits

The Welsh Government answers your questions

Why is a  20mph speed limit being introduced?  

We believe that introducing a 20mph on residential roads and busy pedestrian streets would:

  • reduce the risk and severity of injuries as a result of collisions between vehicles and vulnerable road users
  • encourage more people to cycle and walk
  • make them more attractive for our communities

Will this affect all roads that are currently 30mph?

The new legislation will make the default speed limit 20mph. This will leave local authorities and the 2 Trunk Road Agencies who are best placed to engage with the local community to decide which roads should remain at 30mph.

Will the police enforce the proposed 20mph speed limit?

The police will continue to enforce all roads. We have been working closely with the police to develop an enforcement strategy which we believe makes our roads safer for all users. We are currently trialling enforcement in pilot areas, ahead of the 20mph national implementation in September 2023.

What effect will the speed limit have on journey times?

Journey times on roads in urban areas tend to be determined by junctions and signals, rather than the speed limit.

In many cases lowering the speed limit to 20mph will have little or no impact on journey times. Where there is an impact, our analysis showed us that most journeys would only be around 1 minute longer but this would make the roads safer for pedestrians and cyclists.

Why can’t the 20mph limit be set up as timed limits during school hours only?

This won't encourage children to walk or cycle from home, as it would only protect children near the school, where they already have safety in numbers.

80% of child casualties are on non-school trips. Introducing a 20mph default speed limit will make children safer from the moment they leave home - it is designed to make streets safer for everyone.

Will the roll out involve money being spent on speed bumps?

There is no plan to include traffic calming (including speed bumps) as part of the change to speed limits. There are other ‘softer’ measures that might be introduced, such as using buffer speed limits, removing the centre line, narrowing the carriageway visually, using planting etc.

Will reducing speeds to 20mph damage my car gear box?

Modern cars can drive at 20mph without damaging the engine or components. 20mph limits have been used since the early 1990s and there have been no reported gearbox issues. Using too low a gear at any speed may increase wear on gearboxes.

Using the right gear and driving at a consistent speed will help prolong engine and gearbox life.

Will driving at 20mph mean I use more fuel?

No. Fuel consumption is mainly influenced by the way we drive – driving at a consistent speed is better than stopping and starting. Accelerating up to 30mph can take twice as much energy as speeding up to 20mph.

Why are bicycles allowed to overtake me when I am driving at 20mph?

It is very rare for a cyclist to over-take a motorist at 20mph.

Speed limits in the Road Traffic Regulations and the Highway Code apply to motor vehicles only and not to bicycles. However, the Highway Code states that cyclists should be considerate of other road users.

Where else have 20mph speed limits been introduced in the UK?

20mph speed limits are in force in many of the medium and larger cities in England and Scotland and more rural authorities are introducing larger scale extended 20mph programmes.

If Scotland also sets 20mph default speed limits, up to 28 million people in the UK will live in local authorities where 20mph is normal.

Last Modified: 14/02/2023
For more information contact:

Highways & Traffic


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