Do 20mph speed limits work?

23rd Oct 2023

A report from an independent transport data consultancy has found that roads in Wales that were reduced to 20mph speed limits have only seen a reduction in speed of just 2.3mph.

Statistics from Agilysis found that after a month after the schemes were introduced, drivers were not reducing their speed to the limits.

The new speed limits across Wales have been a hotly-debated topic in recent months, and there has even been a signed petition submitted on the Welsh Government’s website calling for scheme to be cancelled.

The analysis from Agilysis covered a sample area and involved 10,000 vehicle movements.

According to their report, the information was collected automatically from new cars with data collected manufacturers and location technology.

Looking at the changes in speed since the scheme was introduced, after a week, speeds had dropped by 3.1mph. This then increased to 2.3mph after a month.

Author of the report, Richard Owen, CEO of Agilysis stated: “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 of 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.”

What do you make of the report? Should 20mph limits be scrapped in Wales and the rest of the UK? Leave your comments below.