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Accredited official statistics

RRCGB 2025: Background information

Published 30 July 2026

© Crown copyright 2026

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This publication is available at https://www.gov.uk/government/statistics/reported-road-casualties-great-britain-final-results-2025/rrcgb-2025-background-information

About this chapter

This chapter provides background information on the road casualty statistics presented throughout this publication. It summarises how the data are collected, key strengths and limitations of the statistics, important quality considerations and ongoing developments to the STATS19 data collection system.

More detailed information is available in the accompanying guidance and methodology documentation.

1. How the data are collected

The statistics in this publication are based primarily on data collected through the STATS19 system. STATS19 records personal injury road collisions that are reported to the police and occur on public highways in Great Britain involving at least one motor vehicle, horse rider or pedal cyclist, and where at least one person is injured.

Data are provided to the Department for Transport by all police forces in Great Britain using a common national specification, as set out in the document known as STATS20, available from the data collection section of the guidance pages. This allows road safety statistics to be produced consistently across different areas and over time.

The STATS19 dataset contains information about the collision, vehicles involved and people injured, providing the principal source of information used to monitor road safety trends and support the development and evaluation of road safety policy. Full details are available via the above link.

2. Main strengths of the statistics

Road casualty statistics are one of the longest-established transport statistical series in Great Britain, with comparable data available over several decades.

Key strengths of the data include:

  • A nationally consistent data collection system used by all police forces in Great Britain.
  • Detailed information on collisions, casualties, vehicles, road characteristics and circumstances.
  • Comprehensive coverage of road collision fatalities.
  • A long-running time series that enables trends to be monitored over time.
  • Geographic coverage ranging from national to local authority level.

These strengths make STATS19 the primary source for monitoring road safety outcomes in Great Britain, including targets and indicators for the 2026 road safety strategy.

3. Important limitations

Users should be aware of several important limitations when interpreting these statistics.

3.1 Not all collisions are reported

There is no legal requirement for all personal injury collisions to be reported to the police. Comparisons with other sources suggest that while most road deaths are known to the police, a substantial number of non-fatal casualties are not recorded within STATS19.

As a result, these statistics should be interpreted as police-reported road casualties rather than all road casualties occurring in Great Britain.

3.2 Changes in severity reporting

Since 2016, many police forces have changed from traditional reporting systems to new injury-based reporting systems.

These systems generally provide more accurate recording of injury severity but have affected the consistency of reported serious and slight injury figures over time. To ensure that trends remain comparable, adjusted severity estimates are used throughout this publication when reporting serious injuries and killed or seriously injured (KSI) casualties. Guidance on injury-based reporting and severity adjustments is available.

3.3 Changes in reporting behaviour

In recent years, several police forces have introduced online self-reporting systems, allowing members of the public to report collisions digitally.

The introduction of online reporting may have increased the number of less severe collisions reported to police, particularly collisions involving slight injuries, and users should bear this in mind when interpreting recent trends. Further information is available in our report on the impact of online reporting.

3.4 Data quality issues

Details of the collection and validation of STATS19 data are available in the background quality report.

Issues with data collection systems in some police forces during previous years mean that the completeness of collision records cannot be guaranteed in some areas. While these issues are unlikely to have a material impact on national trends, caution should be used when interpreting results for individual police force areas or local authorities.

Details of previous revisions and known data issues are recorded so that users can be aware of any specific issues.

4. Final and provisional estimates

The statistics presented in this annual report are final estimates based on validated data returned by police forces.

Earlier provisional estimates are published before the final validation process has been completed. Differences between provisional and final figures are usually small but can occur following additional quality assurance and updates to the severity adjustment model. A comparison of final and provisional figures by severity, for years up to 2022, is available in the background quality report.

Final estimates will not normally be revised unless errors are identified.

5. Understanding injury severity

The severity of road casualties is classified into three categories:

  • Fatal casualties – casualties who die as a result of their injuries, within 30 days of the collision.
  • Serious casualties – casualties sustaining injuries classified by the police as serious (usually coded from the most severe injury recorded).
  • Slight casualties – casualties sustaining less severe injuries.

For analysis of trends, figures for serious injuries and KSI casualties are based on adjusted estimates that account for changes in police reporting systems.

Detailed information on these adjustments is available in the severity adjustment guidance.

6. Road safety factors

Road safety factors (RSFs), formerly known as contributory factors (CFs), are recorded by police officers when evidence suggests a factor influenced the occurrence or severity of a collision.

RSFs provide valuable insight into the circumstances associated with road collisions but they should not be interpreted as determining blame or legal liability. The factors reflect the judgement of the reporting officer based on the information available at the time.

Multiple factors can be assigned to a collision, meaning percentages relating to RSFs will not sum to 100%.

The transition from the old CFs to the new RSFs has some implications for the consistency of the data over time, which should be kept in mind when analysing the data.

Further information, and our advice on using the data during the transition from the old to the new framework, is available in the road safety factors guidance.

7. User engagement and developments

The Department for Transport regularly engages with users of road casualty statistics to ensure the statistics continue to meet user needs and to identify opportunities for improvement. Users include national and local government, road safety organisations, academics, consultants, the media and members of the public.

Feedback from users informs the development of road safety statistics, including the presentation of findings, publication formats, supporting data products and future analytical priorities. Recent user feedback has contributed to the development of new factsheets, interactive data tools, analysis of emerging topics and the structure of this publication, with a summary of previous feedback and responses available.

Alongside this publication, we are seeking feedback on proposed changes to some aspects of the presentation and dissemination of road casualty statistics, including the organisation of publications, accompanying data products and supporting guidance. Feedback can be provided through our user feedback survey.

The Department continues to work with police forces, National Highways, devolved administrations, road safety partners and other stakeholders to improve the quality, accessibility and usefulness of road casualty statistics.

Information about users, user needs and recent engagement activities can be found in our user engagement section.

8. Ongoing development of STATS19

The STATS19 specification is periodically reviewed to ensure that it continues to meet user needs and reflects changes in transport, technology and road user behaviour.

Recent developments, following recommendations from the most recent STATS19 review in 2018, have included the introduction of new variables, improvements to injury severity recording and the transition from contributory factors to road safety factors.

The Department continues to work with police forces and stakeholders to improve data quality, reduce reporting burden and ensure the statistics remain fit for purpose.

9. Accredited official statistics

These statistics are accredited official statistics and are produced in accordance with the Code of Practice for Statistics.

The statistics are subject to regular quality assurance and are intended to provide trustworthy, high-quality and valuable evidence on road safety in Great Britain.

10. Further information

More detailed information is available through:

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13. Contact details

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