What will be the transport impacts of Clean Air Zones in our cities?

The Occasion

In order to tackle poor urban air quality Clean Air Zones (CAZs) are being established in a number of UK cities to help reduce public exposure to pollutants. These are currently divided into charging and non-charging zones, and a range of options now exist on how widely to place restrictions on vehicles. As a result, the introduction of CAZs is likely to have a significant impact upon transport within our cities. How best should CAZs be framed in order to be both effective and equitable for city residents? And what steps should be taken to reduce the chance of unintended transport consequences?

To introduce this important topic, the ITC was delighted to welcome a distinguished panel from the public and private sectors at its Autumn Discussion Evening on 29th October 2019. The panel included: Mai Jarvis, Environmental Quality Team Manager at Oxford City Council; Steve Gooding CB, Director of the RAC Foundation; and Aart Hille Ris Lambers, UK Commercial Director of DP World. The open discussion that followed was moderated by ITC Chairman Terry Hill CBE.


What will be the transport impacts of Clean Air Zones? Key issues from the speakers:

  • Mai Jarvis provided an introduction from a Local Authority perspective on implementing CAZs. She explained that the CAZ framework allowed cities to develop a zonal charging mechanism to reduce emissions, but flexibility existed over how this was applied. Particular challenges facing her city of Oxford included accommodating a high number of tourists, a large transitory student population, as well as rapid city growth exacerbating traffic congestion. Faced with 75% of Oxford’s air pollution arising from transport, she outlined the attempts that had been made to create a Zero Emission Zone since 2014. A phasing system had been designed, which would introduce increasing restrictions on polluting traffic. Other initiatives included bus pathway and hackney carriage electrification by 2025, regulating parking and city centre access, providing electric vehicle infrastructure and encouraging car club membership. Ms Jarvis noted that enforcement of CAZs was a major challenge, due to the high cost of ANPR cameras, incomplete DVLA database information, and the reluctance of residents to give up their cars. Solutions included the need for an integrated transport strategy, good stakeholder engagement with businesses and residents, and more powers for Local Authorities to manage traffic. It would be important, she concluded, that CAZs did not just transfer pollution to new areas, but actually changed travel behaviours.

    Mai Jarvis explains how to implement CAZs

  • Steve Gooding CB discussed the impact of CAZs on motorists. He pointed out that there was a need to address the realities of travel, including the attachment the public had to their private vehicles. Given the range of possible options for CAZs, he said that a number of concerns needed to be addressed. First, it was important to ensure that CAZs did not unduly punish low-income households unable to afford the latest clean vehicle. Second, some larger, heavier vehicles were an essential aspect of city life (thinking not just of freight deliveries but also refuse collection), and the reality was that most were currently diesel powered.  To avoid public confusion it would be desirable for national government to be slightly more prescriptive about the restrictions that could be applied to avoid confusing discrepancies between schemes. Steve said that it was time transport professionals stopped talking about modal shift and recognised that what they were in reality advocating was a different pattern of trips that could be accommodated by different modes. This could be addressed positively by couching the options in terms of what we want our lifestyles and our cities to be like. In closing he noted that the government had thus far taken a narrow focus on vehicle exhaust emissions solely in areas where EU infraction proceedings were threatened, when a more comprehensive – more positive – approach would have been desirable, as would the need to tackle non-tailpipe pollutants such as brake dust, tyre and road surface wear.
  • Aart Hille Ris Lambers offered a perspective on the freight impacts of CAZs. He explained the challenges that DP World had faced engaging with the City of Southampton’s proposals for a CAZ. Initially, this had penalised HGVs many of which were using the container terminal. However, HGVs were only contributing 11% of NOx emissions in the cities, and the scheme resulted in drivers threatening to boycott Southampton and use other ports, thereby damaging the city’s economy. He explained that following discussions, the City Council realized the problem and changed the proposals to focus on replacing diesel vehicles. It would be important, he noted, to develop a sensible trade-in scheme that did not leave diesel vehicles worthless, perhaps through an incremental charging scheme. A national, rather than a mix-and-match approach was needed to avoid simply transferring the pollution problem from one city to another.

    Steve Gooding offers his perspective on CAZs

Key themes raised in the discussion:

  1. There were calls for central Government to take a greater role in helping establish CAZs. Several guests suggested that more guidance and action was required from central Government to ensure that CAZ implementation was succesful. Some called for CAZs to be imposed nationwide, while others said they would welcome improved national guidelines on the impacts of various CAZ measures. It was noted that Local Authorities outside London often lacked the neccessary funding and regulatory powers to develop effective CAZ schemes. National initiatives such as scrappage schemes, road user charging, and building the necessary infrastructure for clean vehicles would all be important in the fight to improve air quality.
  2. Successful CAZ design requires cross-departmental collaboration. It was noted that many of the air quality policy issues around CAZs extended beyond transport to other departments and required multidisciplinary expertise to solve. In particular, several guests suggested that the NHS and local Public Health officers should be more closely involved in the design and implementation of CAZs. Some expressed disappointment that it had been difficult to engage local health officers with CAZ schemes. Greater collaboration between policy officials, especially in health, would be beneficial for helping to appraise the air quality problem, design related interventions, encourage travel behaviour change and educate the public about the need for CAZs.
  3. More work would be beneficial on the issues surrounding and the impacts of CAZs. There were calls for better impact assessments to consider the effects of CAZs on low-income groups, small businesses and urban commercial patterns. The secondary and unintented effects of CAZ and wider air quality improvement policies, such as diesel vehicle trade-ins, were not widely understood. In addition, it was pointed out that some modes such as rail were often excluded from air quality schemes in spite of the high emissions produced by diesel trains in city centres. However, rail policy was set at a national level which made it difficult for Local Authorities to engage. Furthermore it was clear that urban particulate emissions were also derived from brake, tyre, clutch and road wear: problems which were not currently being widely addressed.
  4. Greater support is required for businesses if CAZ policies are to be successful. Cities rely on their Small/Medium Enterprises (SMEs) to support the local economy and employment, yet CAZ policies could have a major impact on these businesses. This is particularly so since they often rely on HGVs and LGVs to fulfil their logistics and delivery needs, although they do not have the same burden of complex supply chains as major companies. Several delegates proposed that engagement with local businesses should take place early and frequently when designing a CAZ scheme. Incremental and flexible interventions can be introduced to encourage behavioural change without damaging commercial activities. Regulation and measures such as vehicle scrappage will need to be carefully tailored to avoid damaging SMEs, and these might require government assistance to cope with the costs of upgrading to clean vehicle fleets.

    ITC Chairman Terry Hill leads the panel discussion

  5. CAZs should aim at encouraging long-term travel behaviour changes. It was observed that long-term behaviour change should be the goal of policy makers. Some guests pointed out that human travel time per day was fairly constant across history and culture, and so an effective measure would be to shift travel from polluting modes to non-polluting ones, including cycling and walking. Technology alone would not solve the problem, some suggested, so a range of ‘carrot’ interventions would be needed to encourage behaviour change alongside ‘sticks’ such as charging and fines. It was proposed that road user charging would be a valuable mechanism for inducing behavioural change, but all measures should involve good public engagement.