About 20mph for Southampton

A sign indicating a 20 mile per hour speed limit

Southampton City Council is committed to ensuring the city’s streets are safe for everyone who uses them, including having suitable speed limits.

Why 20mph in Southampton?

Making speed limits 20 miles per hour (mph) on residential roads in Southampton brings many benefits to people living here. A 20mph limit helps to reduce the risk and severity of collisions, encourages people to walk and cycle and makes it easier to cross the road - particularly for children, people with mobility issues and older people.

Our long-term transport plan Connected Southampton 2040 and Corporate Plan set out to make Southampton a place where people can easily and safely get around. The safety of people using and interacting with Southampton’s transport network is important and there is a need to continually reduce the number and severity of casualties from transport collisions towards zero. Lower speed limits is one of the tools that help make Southampton a safer place for everyone to travel around. It complements other projects like Safer Routes to Schools, Active Travel Zones and the wider cycle, walking and road network.

To achieve this in Southampton, the council is implementing a phased approach to introducing 20mph speed limits in residential areas of the city where feasible and where there is strong community support. This expands on the existing areas of the city that have already had 20mph speed limits introduced over time.

Benefits of 20mph driving

Driving at 20mph is a more forgiving speed when people make mistakes, as the consequences of those mistakes are less severe the lower the speed of the collision.

There is evidence that as speeds fall the impact of a collision is reduced, so every 1mph drop in speed can significantly reduce the severity of a collision.

There is a wealth of evidence that shows why having lower speed limits in Southampton benefits everyone:

The Royal Society for the Prevention of Accidents

The Royal Society for the Prevention of Accidents (ROSPA) has put together a useful 20mph factsheet, explaining the need for lower speeds to bring down casualty rates, and the evidence behind 20mph zones/limits in reducing vehicle speeds.

Latest national guidance

The latest national policy guidance is also clear that vehicle speeds should be below 20mph on quieter routes, to create safe and comfortable streets for walking and cycling where there is support.

The UN and WHO

Evidence shows that children's reaction times are slower than adults in perceiving gaps in faster moving traffic. The UN’s ‘Streets for Life’ campaign, and the World Health Organisation (WHO) call for 20mph in all areas where people and traffic mix, to promote child friendly streets and reduce child casualty rates.

Vulnerable road users

Studies have also shown that the use of 20mph speed limits will specifically assist other vulnerable road user groups, including people with disabilities and elderly pedestrians. This is of vital importance in reducing the risk of severe injury and helping to maintain independent mobility.

The effect of a 20mph limit on air quality

An evaluation of 20mph zones, carried out by Imperial College, showed slowing traffic had no net negative impact on exhaust emissions, and a smoother driving style reduces particulate emissions.

Where will the 20mph limits be?

The council formally consulted on 20mph in areas where residents submitted requests in early 2022. The areas have been designed to cover wider areas bounded by main arterial roads or natural breaks (for example, parks, rail or water) so the speed limit is coherent and consistent. 

In addition to this, the council has secured external government grants through the ‘Active Travel Fund’ and ‘Transforming Cities Fund’ for Active Travel Zones in St Denys, around St Mark’s School, Polygon and Woolston. These zones will include 20mph limits and physical speed reduction measures. You can find out more about these schemes at Active Travel Fund and Transforming Cities Fund.

When will 20mph be introduced in each area?

We opened an online form for people to submit 20mph requests from October 2021 to January 2022. The council received 47 requests for streets or areas where residents wanted lower speed limits from across the city. Following a review of the requests, 12 areas were proposed to go forward for formal consultation over the coming years, as funding allows.

The areas which have had a 20mph speed limit introduced are:

  • Bassett and Flowers Estate
  • St Denys
  • Shirley and Freemantle
  • Old Redbridge
  • Woolston and Weston (from 13 November 2023)

What happens next?

Consultation dates for additional areas are under review and will be confirmed in due course.

We will be monitoring compliance of the new speed limit to see whether additional measures, such as speed reminder signage or additional traffic calming, are needed to support it.

As each 20mph limit area is completed, we will monitor the impact of the changes on speeds, traffic volumes and casualties and report back, after allowing time for new behaviours and speeds to embed.