Hotspot cameras help cut pollution
AIR pollution plummeted at Welsh hotspots – including Port Talbot – after passing drivers were forced to slow down, new statistics reveal.
Before average speed cameras (ASCS) were installed on trunk roads where the speed limit had been cut to 50mph, signs appealing to drivers to consider local residents’ health had relatively little effect.
But once ASCS threatened to hit drivers in the pocket, up to 97.7% of vehicles were recorded as complying with the 50mph limit.
The statistics, released under the Freedom of Information Act, cover January 2018 to February 2020. They exclude traffic changes caused by Covid19 travel restrictions.
In June 2018 the Welsh Government took the unprecedented step of
reducing the speed limit to 50mph at five locations for environmental, rather than safety, reasons.
Now it is considering whether to take similar measures at two other locations, both in South Wales.
According to Public Health England (PHE), air pollution is the biggest environmental threat to health in the UK. PHE estimates that between 28,000 and 36,000 deaths a year are attributed to longterm exposure, and says there is strong evidence that air pollution causes the development of coronary heart disease, stroke, respiratory disease and lung cancer, and exacerbates asthma.
Although the health purpose of the new 50mph limits was widely publicised, the mean traffic speed on the affected roads in Pontypridd and Deeside, Flintshire, was 58mph during the first year of the 50mph limits.
Compliance was also
low at Port Talbot and Wrexham.
In response, the government installed average speed cameras and signs in summer 2019.
In all five locations, the reduction in NO2 was much greater after ASCS than before. From February 2018 to February 2020, recorded NO2 reductions were:
39.5% on the M4 junctions 41-42 at Port Talbot;
47.3% on the A470 Upper Boat to Pontypridd: ■ 41% on the M4 junctions 25-26 at Newport;
22.4% on the A494 at Deeside; and,
32.3% on the A483 near Wrexham.
Other statistics reveal that on both M4 sections NO2 concentrations rose from January 2018 to January 2019 – after the 50mph limit was introduced – but were lower in January 2020 than in January 2018.
Data from the ASCS shows that in most months from August or September 2019 to February 2020,
more than 92% of traffic complied with the 50mph limit.
The highest compliance was 97.7%, on the M4 westbound at Port Talbot in January 2020, with eastbound compliance not much lower at 95.4%. In the same month, compliance was 97.5% at Deeside, 96.1% westbound at Wrexham and 94.4% at Pontypridd eastbound.
No compliance figures were available for the M4 at Newport.
A Welsh Government spokesman said: “We introduced 50mph speed limits as they have the potential to bring immediate improvements to air quality.
“We have achieved encouraging reductions in pollution levels since they were introduced, and we will consider their suitability for other locations where poor air quality has been identified.”
The government is identifying options to address NO2 exceedances along the A470 “north of Cardiff” and on the M4 near Llandarcy, north west of Port Talbot. It will provide an update on these locations next month when it publishes its revised Air Quality Plan.
The government said last month that the ASCS on the M4 at Port Talbot were used only for monitoring, without fines for speeding. Asked whether it was concerned that this public knowledge would result in lower compliance and higher pollution, the spokesman said the government would also provide an update on the next steps for “further action” against drivers exceeding the speed limit.
This would be in partnership with the police and Gosafe, the national speed camera operator.
“Compliance with the speed limit is considered essential if we are to continue with the positive reductions in nitrogen dioxide levels,” he added.