Congestion in London is now worse than when the ultra-low emission zone (Ulez) zone launched five years ago, undermining the benefits of the clean air scheme.
New figures show that the daily average congestion level in the capital was 45 per cent last year, up from 37 per cent in 2019, when Sadiq Khan, the mayor of London, launched the scheme.
TomTom, the geolocation technology company, determined the “congestion level percentage” by calculating the extra travel time a driver would experience compared with free-flowing traffic.
Khan has long insisted that the aim of the zone was to improve air quality by spurring people to buy cleaner cars. However, a year after its launch in central London the mayor’s office published a report which said the scheme “had already helped reduce traffic in the central zone by approximately 10 per cent”.
Experts argue that the rising levels of congestion, caused in part by the rise in 20mph zones and poor traffic management, is a significant cause of emissions, even if more vehicles on London roads meet Ulez standards.
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The zone was controversially expanded last year to cover the whole of London with a new boundary reaching Buckinghamshire, Essex, Hertfordshire, Kent and Surrey. Previously, the boundaries of the zone were the North Circular and South Circular roads.
Last year London was the slowest city out of 387 globally to drive a six-mile journey, according to the TomTom traffic index. This pushes up emissions from idling vehicles.
Andy Marchant, a traffic expert at TomTom, said that programmes that aim to tackle rising traffic emissions, including Ulez, “remain essential to supporting the UK’s ambition to reach net zero by 2050”.
However, he added: “It should be coupled with long-term action. Our analysis shows that five years on from the introduction of Ulez, London remains the world’s slowest city to drive through. The capital’s fuel consumption and CO2 emissions inevitably increased at the same time, with London’s petrol vehicles having the highest CO2 impact in 2023, emitting 3.56 tonnes of CO2 per 10,000 miles driven.”
Susan Hall, Khan’s Conservative opponent at the mayoral elections next month, said: “It’s no surprise London is the slowest city in the world under Khan. Whether it’s the Ulez expansion, low-traffic neighbourhoods, 20mph speed limits or any of the other ridiculous schemes brought in by the mayor, they all lead one way — a dead end. We need to get London moving again by ending [his] war on motorists.”
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Under Ulez, drivers of non-compliant cars — typically petrol cars made before 2005 and diesel ones from before 2015 — must pay a daily £12.50 charge. The scheme’s expansion last summer led to a clash between drivers in outer London and the home counties and Transport for London, which is responsible for installing the cameras.
Campaigners accuse the mayor of using Ulez as a money-making scheme and have questioned its benefit to the environment. The expansion became a dividing line in last July’s Uxbridge & South Ruislip by-election, allowing the Tories to hang on to the seat after the resignation of Boris Johnson.
The daily charges cost London motorists more than £5.3 million in the first week of the expansion, between August 29 and September 4, after the number of charges leapt by almost 300,000.
A spokesman for Khan said: “The evidence shows that Ulez is working, with 95 per cent of vehicles seen driving on London’s roads now compliant and don’t need to pay a penny.
“Sadiq has always been clear that the Ulez should not operate in isolation when it comes to tackling dirty emissions. That’s why under his leadership London’s transport is now cleaner than ever, with 1,400 zero-emission buses on London’s streets, a third of the UK’s electric charging points and a fivefold increase in protected cycling lanes.”
