29th October 2025
How many?
Imagine if for every person reported seriously injured in a collision, there were another three seriously injured, but that these were not reported to and by the police.
That is the reality in Britain. Based on Department for Transport’s (DfT) National Travel Survey (NTS) findings, 120,000 people were seriously injured in crashes in 2024, 92,000 more than the 28,000 reported in official STATS19 data.
Credit to the DfT for undertaking research into under-reporting and for so many years. This is not a new problem. Under-reporting has been known to be a problem for many years—and not just for those slightly injured. There is little difference in the under-reporting of serious injuries compared to slight injuries, (4.4 times as many slightly injured not reported compared to 4.3 times for seriously injured).
What is new is the increase in last year’s under-reporting estimate. This suggests fewer injured people are bothering reporting to the police. Two groups showed the biggest rise, cyclists and children. Cyclists are known to have the lowest reporting rates but in 2024, their adjustment factor jumped from 5.4 to 8.9. So just 11 out of every 100 cyclists injured in 2024 are thought to have bothered with reporting to the police. Injured cyclists account for 20% of total injured adults, instead of 10% in STATS19.
The increase in under-reporting with children injured in crashes was even greater. The adjustment factor for children went from 1.7 in 2023 to 5.2 in 2024, with over three times as many children injured in collisions in 2024 than are reported in STATS19.
For more information, read AVZ’s new briefing on under-reporting which highlights the problem and shows the DfT’s under-reporting estimates dating back to 2011.
How much do they cost?
The DfT also produces annual estimates of the total value of prevention of road collisions. Its 2024 estimate jumped 30% to over £55 billion. This was due to collisions with the unreported casualties mentioned above (accounting for 65% of the total value of prevention).
AVZ has also summarised the valuation of road crashes in Britain. See that for more information on the total cost, which is adjusted for under-reporting, and also about average cost by crash severity. The latter is not adjusted for under-reporting leading to an underestimation of the need and the benefits of road safety programmes.
The real question is why is so little thought given to under-reported casualties. The Safe System, Vision Zero and road safety programmes in general, are focused on reducing reported road deaths and serious injuries. Yet as highlighted above, this is a fraction of those thought to be seriously injured (19%) and a fraction of the total value of prevention. The true toll of road casualties deserves to be tackled, starting with the adjustment of average costs and local/regional costs of crashes.
actionvisionzero.org 
It is well known and to be expected that minor injuries are significantly under-reported, but it is also likely that the NTS is overreporting for a variety of reasons:
The NTS only asks people if they were injured and the type of injury, not if they were “seriously” injured which is a classification assigned by the police to reported accidents. The DfT table does include estimates for numbers of serious/minor but looking at the results, the split of serious and slight has clearly been derived simply by applying the overall result to the individual figures from STATS19, so they don’t mean anything. Obviously, minor injuries are far more likely to not be reported than serious ones. More here
https://assets.publishing.service.gov.uk/government/uploads/system/uploads/attachment_data/file/244916/rrcgb2012-04.pdf
As regards the under-reporting of cyclists, note this: “The principle reason for the estimated high levels of under reporting of the number of pedal cyclist casualties, compared with those recorded in STATS19, is the number of casualties in accidents involving no motor vehicle (of which very few are recorded in the police data) – 42 per cent of pedal cycle casualty respondents in the NTS reported involvement in a single vehicle accident compared with 3 per cent of pedal cycle casualties reported as being in a single vehicle accident in STATS19.”
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