Official Statistics

Linking police and fire road collision data: trends and further analysis

Updated 29 May 2025

Applies to England

© Crown copyright 2025

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This publication is available at https://www.gov.uk/government/statistics/linking-police-and-fire-road-collision-data-an-initial-feasibility-study/linking-police-and-fire-road-collision-data-trends-and-further-analysis

1. About this release

This report is based on linking police data on reported road casualties (collected via the STATS19 system) with data from the Incident Recording System (IRS) on road traffic collisions (RTCs) attended by fire and rescue services (FRSs).

STATS19 is a database comprising information on all personal injury RTCs occurring on public highways and reported to the police within 30 days. IRS is a record of all incidents attended by Fire and Rescue Services (FRSs) in England maintained by the Home Office fire statistics team.

This study follows on from an initial analysis of the linked dataset, and was conducted to analyse further years of data including trends over time. The linked dataset covers the decade to 2020. This report gives an overview of the linking of the two datasets as well as key statistics and trends on collisions recorded both by police and fire services.

Alongside this high-level report, data tables have been published including underlying figures summarising the linkage, including at police force area level.

2. Main findings

The aim of linking the two data sets is to enhance the value of STATS19. This includes understanding whether trends in the number of collisions shown by the two datasets are similar.

Overall, there was a steady decrease in collisions reported by police and fire services in the linked dataset, between 2011 and 2019. There was a sharp decrease in 2020, which is likely due to the COVID-19 restrictions in place in that year.

Further findings show:

  • for the majority of police forces, trends shown by police and fire service data broadly follow the national pattern; however, potentially due to differences in local reporting practices, some forces show notably different patterns
  • the majority of IRS collisions were linked to STATS19, and the linkage rate was relatively stable across the time period for which data were linked
  • even though more slight collisions appear in the linked dataset (due to a higher number of slight collisions taking place), fatal and serious STATS19 collisions have a higher matching rate to IRS incidents
  • there is a higher matching rate to IRS data for STATS19 collisions on motorways compared to other road classes, which likely reflects that these collisions are more likely to be attended by fire and rescue services

This analysis has been used to inform engagement with STATS19 data suppliers to understand the collection and use of the data. A summary of this work is available from the STATS19 guidance pages.

3. Introduction

The aim of linking the two data sets is to enhance the value of STATS19. Data recorded by FRSs through the IRS include variables that are not recorded by STATS19, therefore linking to STATS19 can provide more detailed information on the type of collisions that require fire service attendance.

Comparing trends in collisions from the two sources may also help in understanding potential recording issues and variations across the country, and a basis for exploring further with data providers as part of wider work to quality assure the STATS19 data.

3.1 Data and linking methodology

DfT received a subset from the Home Office IRS dataset for a period between 2011 and 2020 for non-fire incidents defined as ‘RTCs’. STATS19 data was linked with this subset. This category does not include road vehicle fires. The Home Office only has jurisdiction for fire policy in England and therefore data is for England only. Further details of the datasets linked are summarised in the initial feasibility study.

The linking methodology was an improved version of the methodology used for a feasibility study DfT published in 2022, as described in the initial feasibility study. Neither the IRS extract or the STATS19 data contain a common unique identifier that would allow for a direct and unambiguous linking of RTC records across the two datasets. Instead, the following variables were used for linkage:

  • time and date of call (compared to RTC date and time in STATS19)
  • X and Y co-ordinates (compared to the Easting and Northing recorded in STATS19)

A dataset of potential matches was created where all records from the IRS dataset were matched to all RTCs in STATS19 which occurred within the same day. The difference for both the location and time variables between the IRS and STATS19 dataset was calculated for every potential match.

To exclude unlikely matches, some tolerance was allowed in the degree of agreement on these variables. Only linked records with the following criteria were classed as possible matches:

  • a difference in distance of under 1 mile
  • a time difference of under 30 minutes

A range of time and distance difference thresholds were tested, leading to the selection of the thresholds outlined above (which are stricter than in the original study). Additional variables such as casualty age and sex were evaluated for their potential use in the linking methodology; however, they were found to have limited value and were therefore not included in the final approach.

Due to the linkage approach, there will be both incorrectly linkages and missed matches. While detailed inspection of a sample of linked records suggests that the majority of matches are likely to be correct, it has not been possible to quantify the extent of these issues. While they are unlikely to affect the high-level conclusions shown, they should be kept in mind in interpreting the more detailed results.

3.2 Severity adjustment

The figures in this report for injured casualties are based on adjusting figures reported by the police to take account of changes in the reporting of injury severity by some police forces in recent years. These adjusted figures can reliably be used to compare trends over time across the country. More details can be found in our severity adjustments guidance.

3.3 Impact of coronavirus (COVID-19)

Recent trends in reported road casualties have begun to normalise after the national restrictions implemented from March 2020 onwards following the coronavirus (COVID-19) pandemic. Many of the trends discussed during this report may see the impact of COVID-19 restrictions.

More details about the coronavirus restrictions can be found in Coronavirus: a history of English lockdown laws (England only).

Chart 1 shows the trends of collisions recorded by the police by severity and the trend of collisions recorded by fire and rescue services, in England between 2011 and 2020.

The number of fatal collisions recorded in STATS19 between 2011 and 2020 is relatively stable, serious and slight collisions decreased. IRS collisions (not broken down by severity) showed a stable trend between 2014 and 2019. The sharp decrease seen in all trends between 2019 and 2020 is due to the COVID-19 restrictions.

Chart 1: Trends of collisions recorded by police (fatal, serious, slight) and by fire services (all collisions), England: 2011 to 2020

Chart 2 shows the trend of collisions that appear in the linked data set, in England between 2011 to 2020.

A general decrease in the linked collisions between 2011 and 2019 is seen. The sharp decrease between 2019 and 2020 is likely to be due to the impact of COVID-19 restrictions.

Chart 2: Trend of collisions that appear in the linked dataset, England: 2011 and 2020

4.3 Severity breakdown of linked collisions

Chart 3 further breaks down the trends of linked collisions by severity, which shows that the majority of linked records were for collisions recorded as slight in STATS19. It shows that there were more slight collisions recorded by police and fire services. This is because the majority of RTCs in the overall STATS19 dataset are slights.

Specifically, of all STATS19 collisions 1% were fatal, 16% were serious and 83% were slight. This compares to 6% fatal, 31% serious and 63% slight in the linked dataset – there are a higher proportion of fatal and serious collisions in the linked data as these incidents are more likely to be attended by FRSs (see section 4.4. below).

Chart 3 and Chart 1 show that the patterns for linked collisions broadly match the patterns seen for STATS19 collisions for each severity.

Chart 3: Trends of collisions that appear in the linked dataset by collision severity, England: 2011 to 2020

4.4 Matching rate by severity

Fatal and serious collisions attended by the police are more likely to be attended by fire services as well. The proportion of slight collisions appearing in the linked dataset is notably smaller compared to the proportion of slight collisions recorded in STATS19.

Table 1 shows the matching rate of STATS19 to fire collisions in England between 2011 to 2020.

Table 1: Numbers and percentages of STATS19 collisions linked to IRS collisions by collision severity, England: 2011 to 2020

Severity Number of STATS19 incidents Number of linked incidents % linked to IRS
Fatal 13,888 5,664 41
Serious 238,339 30,301 13
Slight 939,971 52,265 6

Chart 3 and Table 1 show that although there is a higher number of slight collisions recorded, a higher matching rate for fatal and serious collisions (FSC) is seen. Because of the relatively low matching rate for slight collisions, trends in fatal and serious collisions (FSC adjusted) for linked and STATS19 collisions are explored in the following sections.

The IRS dataset does not provide a breakdown of severity of any casualties involved. Therefore, for this section (Chart 4 and Chart 5) fire collisions include all incidents, while STATS19 and linked collisions are filtered to FSC adjusted collisions only.

Chart 4 shows the overall national trends for STATS19, fire and linked collisions. For England as a whole, there is a higher number of STATS19 FSC collisions recorded by the police, then fire collisions recorded by FRS and the linked FSC collisions. While the trends over time are broadly similar, there is a larger reduction in the STATS19 data than for the fire or linked datasets.

There are several potential explanations for this pattern, all of which could contribute to the pattern shown. It is likely that the FRSs will record fewer collisions than are reported to police (there will be some collisions in STATS19, for example involving pedal cycles, where it would be unlikely that fire service attendance is required).

The lower number of linked collisions compared to fire collisions indicates that there are some collisions appearing in the fire service dataset which do not appear in STATS19. This discrepancy is at least in part due to the exclusion of slight collisions for linked collisions in this analysis, but it could also reflect the quality of the linking methodology or under-reporting of collisions in the police dataset.

Chart 4: Trends of STATS19 and linked fatal and serious collisions (FSC adjusted), and all fire collisions England: 2011 to 2020

A further breakdown of the trends by police force is shown in Chart 5. This breakdown revealed three main patterns including:

  • police forces that broadly follow the overall national trend (such as Cambridgeshire, Essex and the majority of forces)
  • forces that do not follow the overall pattern (such as Norfolk, Staffordshire, West Midlands)
  • forces that follow the overall pattern but have irregular changes along the timeline (such as Greater Manchester, Surrey, Thames Valley, West Mercia)

Forces that do not follow the overall pattern and forces that have irregular changes have varying trends. That indicates that explanation for these trends is more likely to be due local circumstances - for example variations of recording practices for each police force or FRS, or issues with the quality of data used for linkage - rather than a consistent factor for the collisions.

The forces in Chart 5 were selected for illustrative purposes to represent the three main patterns described above. Figures for all forces are available in the accompanying data tables.

Chart 5: Trends of STATS19 and linked fatal and serious collisions (FSC adjusted), and all fire collisions for selected police forces: 2011 to 2020

5. Analysis of linked collisions

This section explores variables that are not common for both datasets. For variables included in STATS19, statistics that involve collisions recorded by police that had a corresponding linked record in incidents recorded by FRSs are explored. For variables included in IRS, statistics that involve incidents recorded by FRSs that had a corresponding record in collisions linked recorded by police are explored.

5.1 Road class

Chart 6 shows the percentages of STATS19 collisions that were linked to fire incidents by road class, in England for the period 2011 to 2020 as a whole.

Chart 6 suggests that a higher number of collisions that appear in the linked dataset took place on motorways, compared to the proportion in the STATS19 dataset overall. This is likely to be related to more serious collisions taking place on this road class. However, there are other factors that could explain that trend.

Chart 6: Percentages of STATS19 collisions linked to fire incidents by road class, England: 2011 to 2020

Road class Linked to IRS
Motorway 11%
A road 8%
B road 8%
Other roads 6%

5.2 Fire service type

The fire service type breakdown is only recorded in IRS. Linking this variable to collisions recorded by police adds value to the STATS19 dataset, by enhancing the knowledge we have on which collisions require FRS attendance.

Table 2 shows that there is a similar number of incident for “Make vehicle safe” and “Extrication of person”. However, out of these two service types it is more likely for “Extrication of person” to have a corresponding STATS19 collision. Additionally, the “Make vehicle safe” service type incidents are more likely to be slight collisions and therefore potentially under reported in STATS19.

Table 2: Numbers and percentages of fire incidents linked to STATS19 collisions by fire service type, England: 2011 to 2020

Type of IRS incident Number of incidents Number of matched incidents % linked to STATS19
Extrication of person(s) 54,361 38,514 71
Medical assistance only 9,956 6,525 66
Other 5,063 3,175 63
Release of person(s) 12,033 7,505 62
Make scene safe 20,049 12,097 60
Wash down road 907 527 58
Make vehicle safe 32,059 17,674 55
Stand by - no action 3,304 1,827 55
Advice only 846 386 46

6. Next steps

This study revised and improved the linking methodology of police and FRS data, as well as explored trends in linked collisions and various breakdowns that help understand which STATS19 collisions require FRS attendance. The findings of this analysis provide avenues for future research.

The proposed next steps, subject to agreement from the Home Office, include:

  • further analysis of more variables recorded in each dataset to drive further insights about road traffic collisions
  • engagement with road safety stakeholders to assess potential wider use of the data outside DfT
  • engagement with police forces to understand if trends that deviate from the overall national trend is due to local factors

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9. Contact details

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