In 2023, the decision by Labour Mayor Sadiq Khan, to expand the Ulez to cover all London boroughs, was met with significant public and political opposition.
Five Conservative-run councils even challenged the decision in the High Court – but eventually lost.
And in July last year, Sir Keir Starmer said there was “no doubt” the issue was the reason his party failed to win the Uxbridge and South Ruislip by-election.
Neil Garratt, member of the London Assembly and leader of the city’s Conservative Group, said: “This study confirms what we have been saying all along, which is the benefits of the Ulez in central London, which the study is looking at, are large and the costs are quite small.”
However, he said that the recent expansion to the outer areas has diminished these benefits because “the alternatives to your car are almost non-existent”.
Dr Xiao said: “The Ulez is one effective policy measure, among other complementary initiatives, including providing more accessible public transport and providing safer walking and cycling infrastructure.
“So decisions to introduce similar policies should consider local context, such as existing air quality initiatives and transportation needs.”
The paper, external was based on the travel patterns of children for just one year after the Ulez was introduced. But the broader study, called Chill, has been surveying children and the way they travel to school for the last five years.
Dr Griffiths said the team now plans to evaluate the most recent data to see if the Ulez’s initial impact of the has been maintained.