Study suggests London's ULEZ contributed to emissions cuts as other cities prepare CAZ launches

Thu 24 February 2022 View all news

New research looking at London traffic trends for 2021 shows that CO2 emissions from traffic were cut by 5%, while particulate matter (PM) emissions fell by 40% and NOx emissions were reduced by almost 54%. London's Ultra-Low Emission Zone (ULEZ) was launched in Spring 2019 and expanded in autumn 2021.  Meanwhile, February saw updates about the implementation of new regulations intended to cut air pollution in several English cities.

The annual TomTom Traffic Index, a report detailing London traffic trends throughout 2021, shows CO2 emissions reduced by 5%, while particulate matter emissions fell by 40% and NOx emissions were reduced by almost 54% in the capital.

For the first time, TomTom's annual Traffic Index used traffic data and a methodology devised by academics from Graz University of Technology, to measure the environmental cost of London’s congestion.   

In 2021 alone the index showed that 14.8 megatonnes (Mt) of CO2 was emitted due to the capital’s road traffic, of which 15% (2.2Mt) was a direct result of congestion. London’s average CO2 emissions during a free-flow traffic day were 29,100t, while a congested traffic day caused this figure to rise to 48,300t. 

An earlier study published in 2021 by Imperial College found modest improvements in nitrogen dioxide levels in London following the ULEZ introduction but that other long-term measures had contributed more to improved air quality in the capital. The Imperial study suggested that ULEZ-type measures work best when combined with a broader set of policies that reduce emissions across sectors like bus and taxi retrofitting, support for active and public transport.

Meanwhile, Oxfordshire County Council in partnership with Oxford City Council has today launched Britain’s first-ever zero emissions zone (ZEZ). (See news link.) This means that all polluting vehicles, such as petrol, diesel, and hybrid cars, will be charged for entering the city centre with only zero emission vehicles, like electric cars, able to enter the pilot zone for free.  The pilot scheme will work in a similar way to the London congestion zone charge and the ULEZ.

The charge to enter Oxford's ZEZ will vary from £2 a day to £10 a day depending on the emissions levels of the vehicle.

In developments across other English cities, Bristol's City Council has confirmed plans to launch its Clean Air Zone (CAZ) in September 2022.  The plans will see motorists charged for entering the CAZ; a £9 payment a day for non-compliant cars, light goods vehicles under 3.5 tonnes, taxis and private hire vehicles. There is a £100 a day for non-compliant HGVs, buses and coaches.

Earlier reports had suggested that the scheme would be launched in June but Bristol Council has denied that the latest announcement constitutes a three month delay.

Leeds City Council is reported to have decided to cancel its plans for a CAZ due to fears it could open it up to legal challenges. A Freedom of Information (FOI) request made by the Yorkshire Post included emails between the Council and the Department for Environment, Food and Rural Affairs (Defra) showing concern on the legal authority of such a scheme.

Leeds Council had announced the CAZ was “no longer required” in October 2020, because air quality had significantly improved following “a dramatic shift to cleaner vehicles”.

It has also been reported that the Government has granted a delay to the introduction of Greater Manchester's CAZ. Manchester now has until July this year to submit a revised plan..

The Mayor of Manchester, Andy Burnham, is reported to have urged the Government to 'take the politics out' of the situation and work together on a solution.

In an earlier development (last December) Bradford Council announced that the introduction of the city's Clean Air Zone has been delayed from January until 'Spring' this year.

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