Barking and Dagenham's proposed expansion of its Controlled Parking Zone (CPZ) scheme has come under scrutiny from councillors concerned about the data used to justify air quality improvements. During a meeting of the Overview and Scrutiny Committee, questions were raised about the reliability of using permit data alone as an indicator of cleaner air.
Councillor Andrew Achilleos, Chair of the committee, questioned the methodology for measuring air quality improvements, suggesting that a decrease in permits for high-emission vehicles might not definitively prove a reduction in pollution. Is that how we're measuring it? By saying that there's fewer gas guzzlers, like permits being provided, and therefore, by default, there are less of those vehicles in the borough and air quality's improved?
he asked.
Officers presented data showing a significant increase in permits for low-emission vehicles and a substantial decrease in permits for high-emission vehicles. Daniel Connelly, Parking and Environmental Design Team Manager, stated that while direct measurement of air quality is challenging, the shift in permit data indicates a positive trend. He added that the council is looking to install air quality monitoring equipment to establish a benchmark.
The permit data tracks vehicles based on their emissions, categorizing them into bands. Band 1 represents low-emitting vehicles (0-50 g/km CO2), while Band 7 represents high-emitting vehicles (over 256 g/km CO2). The data shows a significant increase in permits for low-emission vehicles (333.90%) and a substantial decrease in permits for high-emission vehicles (-85.80%) between the 2021-22 and 2024-25 periods. This emission-based permit system is used to encourage residents to choose lower-emission vehicles.
Beyond permit data, the council considers evidence from London-wide research by London Councils, which demonstrates that introducing CPZ reduces the amount of vehicle travel and unnecessary journeys across London and across the borough.
This research indicates potential reductions in car kilometres travelled (6.9% to 14.3%) and van kilometres travelled (12.3% to 20%). The report also references independent research
and established evidence of the relationship between traffic levels, air quality and health outcomes.
¹
The committee also discussed the broader benefits of CPZs, including improved road safety, reduced congestion, and better access for emergency services.
The proposed expansion, known as CPZ Project 3, aims to increase CPZ coverage to approximately 80% of the borough. This project will be delivered in two phases, with consultation planned for the remaining 20% of the borough. The council plans to ensure a comprehensive consultation process for the remaining 20% of the borough by engaging in pre-engagement drop-in sessions for members,
followed by a statutory consultation
period of at least a month. They will also consult with statutory partners, ward councillors, and residents.
The consultation will involve different design on what that zone would look like, what the conditions might need to be,
and all feedback will be collected and considered. The council also intends to make consultation letters more accessible, with key information at the beginning, and will offer various methods for feedback, including QR codes, links, phone numbers,
and in-person or assisted-digital support for permits.
¹ This evidence is referenced in the Public reports pack for the Overview and Scrutiny Committee meeting on Wednesday 09 September 2026: Public reports pack Wednesday 09-Sep-2026 19.00 Overview and Scrutiny Committee