Question to the Department for Transport:

To ask His Majesty's Government what assessment they have made, if any, of the effects of low emission zones in urban areas on (1) vehicle usage, (2) average vehicle speeds, (3) average vehicle journey times, (4) emissions levels, and (5) overall air quality.

The Government has commissioned a robust evaluation programme for the collection and analysis of air quality, traffic, and behavioural insights data from Local Authority areas implementing measures for the reduction of nitrogen dioxide (NO₂). Case studies give further understanding of how local plans are affecting local groups and businesses.

The Government has published a series of annual reports which set out and discuss the analysis of these evaluation findings. Headline findings from these reports and other analyses give an insight into the effects of Clean Air Zones and other measures on air quality and vehicle fleets in Local Authorities. The 2021 annual report is available to view on the Defra Science Search - AQ0851.