London tops list of world's slowest cities for driving

It took an average of three minutes and 38 seconds to travel one kilometres (0.6 miles) in the centre of London last year, location technology company TomTom said.

Colombia’s Barranquilla was the only one of the 492 towns or cities studied whose roads had an average speed slower than London’s last year.

Reducing speed limits from 30mph to 20mph has been one of Mayor of London Sir Sadiq Khan’s key transport policies as part of his ambition to reduce road casualties.

Transport for London’s website states that more than half of the capital’s roads now have a 20mph limit.

It adds that a person is five times more likely to be killed if they are hit by a vehicle travelling at 30mph rather than 20mph.

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TomTom traffic expert Andy Marchant told the Press Association news agency: “Low average speeds in London are often interpreted as extreme congestion but that misses the full picture.“

Average speeds are heavily shaped by static factors such as the widespread 20mph limits, street design that doesn’t match today’s needs, and consistently high traffic volumes, which means journeys can be slow even when roads are flowing.

“Congestion still matter but in London it adds delay on top of an already constrained baseline rather than being the only cause of slow travel.

”London was the eighth most congested town or city in the UK, based on the percentage of average additional time spent in traffic compared with free-flow conditions.

Belfast had the worst congestion level at 58%, followed by Edinburgh (58%) and Cambridge (54%).London’s figure was 52%.

Drivers in London lost an average of 141 hours stuck in rush hour traffic in 2025, the analysis found.The worst day of congestion in London last year coincided with a Tube strike on September 10.

Mr Marchant added that this year will be an “interesting time for urban mobility”, with trials of autonomous vehicles being rolled out across 20 London boroughs.

A spokesperson for the mayor of London said: “Comprehensive TfL data suggests that journey times on the TfL road network actually remain at similar levels to those in 2019, while analysis from around the UK suggests that lower speed limits have not increased congestion.”

She added: “Studies have shown 20mph limits and zones may improve traffic flow and cut traffic jams.”