12 April 2021

Clean Air Zones and their impact on our road network

What do Clean Air Zones mean for the UK road network?

As you may have seen in the news, Bath has become the first of many areas outside of London to launch a Clean Air Zone (CAZ). This is great news for the planet. But what does it mean for the UK road network? We explore how CAZs work, what effect they’re likely to have on traffic, and how they might change the lives of city residents in the long-term.

What is a Clean Air Zone?

A Clean Air Zone is an area in which a local authority has introduced special measures to improve air quality. They came to prominence in the UK after Government ministers were given orders to try to decrease the levels of nitrogen dioxide in the air, following pressure from environmental activist groups.

Until recently, the UK’s only Clean Air Zone has been in London. It’s known as an Ultra Low Emission Zone (ULEZ) and it covers the whole of central London, including the City and Westminster areas.

The existence of this zone means that diesel vehicles registered before 2015 and petrol cars and vans registered before 2006 have to pay £12.50 every day where they enter the zone. This also applies to motorbikes and mopeds registered before 2007. Buses, coaches and lorries which don’t meet the Euro 6 standards have to pay a hefty £100.

But with UK nitrogen dioxide levels continuing to increase, more and more areas are looking to launch Clean Air Zones. Birmingham, for example, is set to introduce their first CAZ in June. We are also set to see the introduction of CAZs in Bristol, Bradford, Portsmouth, Newcastle, Gateshead, North Tyneside and Greater Manchester — all before the end of 2022.

Another area of interest is heavily-pedestrianised Oxford, whose County Council Cabinet have approved the introduction of a Zero Emission Zone. This will be the first ZEZ in the UK. Its aim is to restrict polluting vehicles from entering key city centre streets during the day to help reduce toxic air pollution levels.

Other organisations are also trying to support the efforts to reduce pollution levels. International infrastructure group and construction company Balfour Beatty has teamed up with Innovate UK, Leeds Beckett University, Hertfordshire University and White Frog Publishing to create a carbon calculation tool for the construction and infrastructure industry.

In addition, back in November 2018, TFL began an innovation partnership with Bosch. We are now starting to see the benefits of this partnership on air quality. The duo recently reported a reduction in air pollution in Lambeth due to the introduction of a new traffic signal timing strategy.

Most importantly, however, is Bath who recently became the first area outside of London to introduce a Clean Air Zone. This CAZ works a little differently to the ULEZ in London. Here’s how.

Bath’s Clean Air Zone

Bath has introduced its new Clean Air Zone because its levels of nitrogen dioxide are currently exceeding legal limits. Nitrogen dioxide can be very harmful to vulnerable citizens such as children and the elderly or unwell; the colourless gas damages the human respiratory tract, and can cause dangerous lung problems.

In 2017, Bath received instruction from the government to attempt to reduce these levels as fast as possible. A CAZ was considered the fastest way to achieve that goal.

The zone covers the majority of the city centre — as can be seen in the map below. You can also check whether your post code lies within the zone here.

Unlike the ULEZ in London, Bath’s CAZ does not currently require private vehicles such as cars and motorcycles to pay to drive through, thanks to new traffic management plans being introduced in Queen Square. These make it likely that fewer vehicles will be allowed to pass through at any one time.

But for now, it’s only high-polluting public vehicles such as vans, taxis, HGVs, buses and minibuses that will have to pay fines.

What counts as a high-polluting vehicle?

  • Any pre-Euro 6 or pre Euro-4 petrol vans, taxis and minibuses will be charged £7 a day to enter the zone.
  • Public HGVs and buses which fail to meet the criteria will have to pay £100 a day.
  • If you own a private HGV or horsebox, the charge will remain at £9 a day. 

While these charges and restrictions are certain to have a positive impact on the air quality in Bath, we wonder what kind of impact they’ll have on the road network.

The impact of Clean Air Zones on our road network

Since the announcements of new Clean Air Zones across the UK, there’s been a lot of discussion about the effect they’re likely to have on our roads.

Some residents in areas surrounding CAZs fear that drivers, in an attempt to avoid driving through CAZs, will take smaller, quieter roads instead – not reducing emissions, just shifting them. This could then see an increase in both nitrogen dioxide and congestion levels in nearby areas, many of which may be rural. Nitrogen dioxide is extremely harmful to vegetation, and can reduce crop yields.

CAZs could also mean that delivery drivers have to take longer routes and will experience delays, creating the possibility of companies refusing delivery in certain areas or charging customers extra for the costs they incur.

At the moment, most CAZs are not charging private vehicles directly. But many are anxious about what the future may bring. If the charges were to expand to include private vehicles, citizens who live inside these zones could face difficulty accessing their own properties. Not only this, but residents might be obliged to switch to more expensive electric vehicles in order to save money long-term. The planet stands to gain, but CAZs are likely to need local support in order to remain sustainable.

For now, however, it seems that local authorities are doing their best to minimise the impact of CAZs on the roads, especially for private vehicle owners.

At one.network, we’ll be monitoring the situation closely to see what effects the CAZ initiatives, and similar schemes around the country, will have on traffic interventions and congestion in our cities.