Average speed in Wales’ 20mph zones ‘down 2.3mph’ – new analysis

Martin Shipton

Average driving speeds in a sample of Welsh roads in Wales affected by the 20mph limit are now running at just 2.3mph less than they were before the scheme was introduced, according to analysts.

Agilysis, the independent transport data consultancy that undertook the original research, has revisited the data one month on from its first report.

The change has been highly controversial in Wales, with more than having signed a petition on the Senedd’s website calling for it to be scrapped.

Although the latest analysis only covers a smaller sample of roads, data from 10,000 vehicle movements shows there has been a slight bounce-back in vehicle speeds.

Data was collected automatically from new cars whose movements are monitored by manufacturers and shared with location technology firm TomTom.

On the roads analysed in the week after the change, speeds had dropped by 3.1mph. The new data shows this is now 2.3mph.

Speeds of the fastest drivers – the top 15% – dropped by 4.9mph after the first week but this has changed to only 3.8mph.

Complacency

Richard Owen, CEO of Agilysis and the report’s author said: “The evidence on this smaller sample of roads indicates there is no room for complacency. Although the majority of motorists are sticking to the limit, there will be concerns about the minority who haven’t adjusted their speed choices enough.

“Understanding which roads are seeing lower levels of compliance could be critical in targeting education and enforcement to achieve better compliance.

“To add some context, the industry usually considers the top 15% – referred to as the 85th percentile – as an indication of where to look at speed management, whether that’s engineering like speed bumps or gates or some kind of enforcement. However it seems no one can yet enforce the 20mph limits anywhere in the UK because the equipment needs to go through a type approval process and the government system is so backlogged and has been for about a decade, things are taking an age to make it all the way through.

“I was at a conference this week where understandably 20mph was raised a few times and they talked about an updated report which reviewed similar schemes in Scotland, Ireland and England and the effect it’s had on casualties. Their argument was that as well as saving lives it was also helping the NHS because fewer people need short- or long-term treatment.”

Enforced

In response to Mr Owen’s comment’ a spokesperson for GoSafe, the Welsh road casualty reduction partnership, said: “We have enforced in 20mph areas for over a decade, using mobile enforcement equipment.

“We are working closely with local highways authorities to ensure that our enforcement can continue to serve the communities in our current 20mph enforcement locations, where the speed limit remains unchanged, and signage is appropriate.

“There are also a number of fixed speed cameras that were installed in 30mph limits, where killed or serious injury collisions occurred, that now sit within 20mph limits.

“We will work with our Highway Authority partners to understand where there are still road safety concerns in these areas, and will commence enforcement using the fixed camera infrastructure, where there will be a road safety benefit in doing so.

Support

A report discussed at the conference from the Parliamentary Advisory Council for Transport Safety (PACTS) states: “Lower speed limits in urban areas (typically 20 mph in place of 30 mph in the UK, and 30 km/h in place of 40 or 50 km/h in mainland Europe) have been introduced since the 1990s. These usually covered relatively small areas. Graz, Austria was the first to embrace a whole city. It was seen as a matter for local policy makers, often within constraints set by central government.

“This has now changed. There is now high-level support for widespread use of lower speed limits (20 mph / 30 km/h) in urban areas, to improve road safety and to support other policy objectives. Lower urban speed limits were endorsed by the UN General Assembly in 2020 and have been adopted in many countries and major cities, including for example Spain and Brussels. Many towns or cities have implemented 20 mph limits, usually in particular areas but sometimes citywide.

“Excessive or inappropriate speed is a major contributory factor to road casualties. Setting and enforcing speed limits is a well-established part of road safety policy. The increasing adoption of schemes like Vision Zero and Safe System has brought about a new approach to speed limit setting. In this context, a safe speed is one at which the road user can withstand a collision without suffering death or life-changing injury.

“This will depend on the safety performance of the vehicle, the infrastructure, the nature of the collision and other factors. 20 mph is now generally accepted as the safe speed for streets used by pedestrians and cyclists. At 20 mph a pedestrian is likely to survive an impact with a motor vehicle whereas at 30 mph the pedestrian is significantly more likely to be killed. Traffic speeds of around 20 mph are also more conducive to walking and cycling.

“The conclusions and direction of change are reasonably consistent. These show a downward movement in speeds and casualties where lower limits are introduced. It is the scale of the movement that is harder to assess.

“The magnitude of the results of individual studies varies, both within countries and between them. However, there is enough commonality to draw the following findings, based on the UK and six European case studies:

* 20 mph limits without physical measures result in modest speed reductions – typically 1-2 mph where before speeds are approximately 25 mph, and reductions of 3-5 mph where before speeds are approximately 30 mph.

* 20 mph limits without physical measures result in approximately 11% fewer casualties than before in the UK.

* For the European case studies, there were approximately 18% fewer casualties after 30 km/h limits were introduced but this figure was for all schemes, including some with physical measures. There were too few studies of sign only schemes to provide an average.

* Some 20 mph limits would have been accompanied by other measures, such as cycling infrastructure which might have contributed to any casualty reductions.

* Compliance with 20 mph limits without physical measures is poor.

* 20 mph limits with physical measures have substantially greater speed and casualty reduction effects than those without.