Between January 2022 and October 2025, there were 1,496 collisions recorded on the M4, according to research by Marshall Motor Group.
The M6 came in second place, with 896 collisions recorded.
Third place was the A1, recording 693 collisions.
Across the UK, 218,817 road collisions were recorded in total between 2022 and October 2025.
The analysis of figures obtained through Freedom of Information (FOI) requests revealed how many crashes police forces recorded each year.
Only forces that responded within the statutory 20-day timeframe and provided complete, usable data were included in the analysis.
Ben Welham, motoring expert at Marshall Motor Group, said: “With more than 57,000 collisions recorded each year, the data on road safety across the UK is concerning.
“Understanding where and why these incidents occur is essential for improving safety.
“While it might be expected due to their popularity, to see over 2,000 collisions happening on the M4 and M6 in less than four years is still worrying.
“These incidents on two of the UK’s busiest motorways, spanning five police force areas in England and Wales, are likely to be caused by a combination of high-speed traffic, frequent merging lanes, heavy goods vehicles and driver fatigue during long journeys.
“The third most dangerous UK road is the A1, also known as the Great North Road. It stretches over 400 miles between London and Edinburgh, so it’s perhaps of little surprise to see it on this list considering the number of vehicles that travel on it daily.”
The data revealed that while collision numbers have fluctuated slightly, there has been a minimal reduction in vehicle crashes over the last four years.
In 2022, there were 59,593 collisions recorded, which decreased 3.17% in 2023 to 57,702.
2024 recorded 57,998 collisions, up 0.51% year-on-year.
January to October 2025 recorded 43,524 collisions in total.
Welham said: “The small decline between 2022 and 2023 offered some hope, but the uptick in 2024 indicates that drivers need to be more cautious, particularly when travelling on roads that are well known for collisions.
“With 2025 already recording more than 43,000 collisions by October, we’re on track for another year of similar figures.
“This consistency suggests systemic issues rather than one-off problems.”
Collision rates vary across the country, with urban areas and major transport corridors experiencing the highest incident rates.
West Midlands Police recorded 29,806 collisions, followed by Gwent Police with 22,382, and Avon and Somerset with 20,075.
Welham added: “The West Midlands’ position at the top reflects the challenges of one of the UK’s largest areas for urban development, covering a large city like Birmingham and several smaller hubs such as Wolverhampton, Dudley, Sandwell, Solihull and Walsall.
“High traffic volumes, complex road networks and dense population all contribute to elevated collision rates.
“Gwent and Avon & Somerset in the top three are likely a result of major motorway corridors running through these areas.
“You’ve got the M4 connecting London to South Wales via Bristol, then the M5 running north-south through England, from the Midlands down to the South West.”
While some areas face high collision rates, others – including those under the jurisdiction of smaller police forces – record much lower incident rates.
For example, City of London Police recorded 990 collisions, with Cleveland Police and North Wale Police recording 2,160 and 2,510 respectively.
Welham said: “The City of London’s especially low figure reflects its tiny residential population.
“Forces like Cleveland and North Wales have lower traffic density and fewer major motorway networks passing through their areas, which is reflected in their collision figures.
“Understanding collision patterns can help drivers navigate the UK’s most dangerous roads more safely.
“Traffic flow and road layout are big factors in collision risk.
“On motorways, drivers are travelling at higher speeds and changing lanes often, which increase the chances collisions.
“Merging lanes can also create dangerous situations when drivers misjudge speeds or fail to check blind spots properly.”
Welham added: “Plan breaks on long motorway journeys and stay alert, especially during afternoons and evenings when concentration levels can naturally dip.
“Beware of tailgating and maintain proper following distances at high speeds, paying extra attention at merging points.
“The Highway Code tells drivers to allow at least a two-second gap between your Audi and the vehicle in front on roads with faster-moving traffic, and in tunnels where visibility is reduced.
“As speed increases and weather conditions deteriorate, the gap needs to be wider.”
