ULEZ compliance data

How TfL measures and reports compliance levels

Compliance levels in London are monitored through Automated Number Plate Recognition (ANPR) data derived from anonymised daily camera detections. To check if a vehicle meets the ULEZ standards or not, we cross-reference this data with available DVLA records, including information on vehicle type, age, Euro standards and emissions. This gives us a daily average compliance rate for each month for central, inner and outer London.

The compliance levels of vehicles on London roads over time have been published in peer-reviewed reports assessing the impacts of the ULEZ, including the London-wide ULEZ first month report.

Following the ULEZ expansion across all London boroughs on 29 August 2023, we are continuing to monitor compliance rates. The data for outer London (in September 2023) shows that across both inner and outer London, 95% of vehicles overall seen driving in London on an average day now comply with ULEZ emissions standards.

Daily average total number of cars detected in outer London, September 2023 Daily average number of compliant cars detected in outer London, September 2023 Daily average number of non-compliant cars detected in outer London, September 2023 Proportion of cars that are compliant with ULEZ detected in outer London, September 2023 (compliant detected/total detected)
1,457,000 1,405,000 52,000 96.4%

Additional cameras have now been installed in outer London for the expanded ULEZ. Data from these cameras has been analysed as part of our ongoing monitoring of the scheme. The compliance rate of vehicles registered to addresses within inner, central and outer London has been lower than the compliance rate of observed vehicles in each of those zones.

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