Most motorists are still keeping to the new 20mph speed limit on many Welsh roads, sample data suggests.
But there appears to have been a slight “bounce-back” after initial figures suggested a dramatic drop in speed after the new default limit came in.
Independent transport consultants Agilysis went back to two sample routes in Cardiff and Wrexham a month on.
It found speeds had dropped by 2.3mph – but this compared with a fall of 3.1mph in the first week of the new limit.
The analysis involved TomTom data covering about 10,000 vehicle movements last week along B4487 Newport Road in Cardiff and A5152 Chester Road in Wrexham.
This compared with a much larger sample of nearly 30 million vehicle movements in Wales in the week after the new limit came in on 17 September.
It also showed speeds of the fastest drivers – the top 15% – dropped by 4.9mph after the first week but this had changed to only a 3.8mph reduction last week.
The original research compared speeds before and after the new limit came in.
Richard Owen, chief executive officer 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.”
Official figures on vehicle speeds are not expected before spring 2024, while updated data from pilot areas is due later this year.
The policy change has brought opposition, with the Welsh Conservatives saying while they were in favour of a 20mph limit outside schools, hospitals and care homes, but a “blanket rollout” was “disastrous, frankly ludicrous and a war on motorists”.
The Welsh government has insisted the impact on journey time would be “small”.
It has also been supported by organisations ranging from Friends of the Earth Cymru and Action for Children to Sustrans Cymru
Why has Wales gone to 20mph?
The Welsh government said the 20mph national speed limit would reduce road collisions, road deaths, noise and pollution while encouraging more people to walk or cycle.
Latest official figures show more people were killed or seriously injured in 30mph zones in Wales last year than at any other speed limit.
Of the 1,014 people killed or severely hurt on Welsh roads in 2022, more than 40% (421) were hit on a 30mph stretch of road.
Of the 22,000 miles (35,171 km) of road in Wales, an estimated 7,700 miles (12,500 km) has changed from 30mph to 20mph.
But about 3% of 30mph roads have exemptions, after applications by local councils.
Source : BBC