Supporting Information

This publication presents detailed statistics about the circumstances of personal injury road accidents in Scotland that were reported by the police using the Stats 19 statistical returns.

Given their size and detail, the tables referred to throughout the text are published separately. These tables are available as excel files on the Reported Road Casualties publication page.

Each accident is classified according to the severity of the injury to the most seriously injured person involved in the accident. These statistics are used to inform public debate and support policy on road safety (through education and engineering programs).

This publication also includes statistics related to further analysis on specific road safety topics. For example:

Valuation of road accident and casualties: Table 9 presents estimates of the value of preventing reported road accidents in GB and Scotland, based on DfT analysis.
Drink drive estimates: Table 22 presents estimates of the levels of accidents and casualties involving drivers and riders with illegal alcohol levels using Procurator Fiscal data.

The status of the statistics

Most of the data used in this publication were extracted from Transport Scotland's Road Accidents statistical database on the 12 September 2022. The statistics given here may differ slightly from those published elsewhere (e.g. provisional figures published in Key Reported Road Casualty Statistics in June) because they were extracted on a different date and wouldn't incorporate any later changes (e.g. due to late returns or late corrections). Any late returns will be incorporated into the next available publication.

The information held in Transport Scotland's Road Accident Statistics database was collected by the police following each accident, and subsequently reported to Transport Scotland. Transport Scotland's statistics may differ slightly from the local authorities as changes or corrections that local authorities may have made, for use at local level, to their own data may not always be accounted for in the Transport Scotland database.

In mid-2019, Police Scotland started to use a new accident recording system. The introduction of this new system has changed the way casualty severity is recorded, making direct comparisons difficult. For the years 2004 to 2019, this publication uses figures for slight casualties, slight accidents, serious casualties, and serious accidents that have been adjusted in order to maximise comparability with figures for the most recent years. This does mean that the figures for serious and slight accident and casualties are not comparable prior to 2004. More information is set out in the following section.

Changes in severity reporting and 'adjustments' to figures

In the summer of 2019, Police Scotland started using CRASH (Collision Reporting and Sharing), an injury-based reporting system, for recording the data that feeds this publication. Before the introduction of CRASH, police officers would use their own judgement, based on official guidance, to determine the severity of the casualty (either 'slight' or 'serious'). CRASH is an injury-based recording system where the officer records the most severe injury for the casualty. The system then automatically converts the injuries to a severity level from 'slight' to 'serious'.

Since CRASH removes the uncertainty that arises from officers having to assess the severity of casualties based on their own judgement, severity information collected in this way is expected to be more accurate and consistent. However, the move to an injury-based reporting system tends to result in more casualties being classified as 'serious', which means that the number of serious and slight casualties are not comparable with earlier years.

The Department for Transport has carried out analysis which adjusts historical figures so that they reflect the numbers that would have been reported if CRASH had been used to record the casualty severity in those years. Within this publication, these adjusted figures are used to report on serious casualties, serious accidents, slight casualties, and slight accident for the years 2004 to 2019. This means that the adjusted figures for 2004 to 2019 are comparable with figures for 2020 and 2021, but not with figures for years prior to 2004.

As the adjustments relate only to serious and slight casualties, figures for total casualties and fatalities are unaffected

More information on the methodology used to produce these adjusted figures is available from the Department for Transport.

The years covered in the tables

Some tables present a time series so that any trends can be identified. However, more detailed tables provide figures in the form of 5-year annual averages (e.g. 2017-2021), and do not present figures for the latest single year. This smooths out levels of variation often present with low numbers of accidents and casualties. If readers require versions of the detailed tables for single years, these can be provided on request.

Road casualty reduction targets

In many of the tables, the latest figures are compared with the annual averages for th period 2014-18. This is to allow comparison against the baseline period for the Scotland's 2030 casualty reduction targets published within the Road Safety Framework to 2030.

This publication discusses these targets in more detail, monitoring progress and exploring differences between modes of travel. Due to the changes in casualty severity recording, progress against some of the targets is measured using the adjusted figures produced by the Department for Transport, which show what historical figures would have looked like if the CRASH system had been used previously.

Estimates of the total volume of road traffic

Some tables include estimates of traffic volumes, or accident or casualty rates calculated from them. The traffic estimates were provided by the Department for Transport (DfT), which produces estimates of the total volume of road traffic for Scotland and for other parts of Great Britain. Care should be taken when using these estimates and a detailed description can be found in Appendix D of this publication.

Review of Stats 19

National & local government police forces across Great Britain work closely to achieve an agreed standard for the system for collecting & processing statistics on road accidents involving personal injury. The statistics are subject to regular reviews as part of the continued drive to improve quality and meet user needs whilst minimising the burden of collection.

The most recent STATS19 review started in autumn 2018 and has made a number of recommendations on changes to STATS19 going forward. These were based on evidence and detailed discussion with the review group.

Key recommendations can be found in the full STATS19 review report.

For further information please contact: STATS19REVIEW@dft.gov.uk

Office for Statistics Regulation compliance check

In 2019, these statistics were assessed against the Code of Practice for Official Statistics by the Office for Statistics Regulation (OSR). The outcome of the review was that these statistics should continue to be classified as national statistics. More information about the findings of the review is available on the OSR website.

Further details on the role of the UKSA and the assessment process can also be found via the OSR website.

Other Scottish Transport Statistics

Reported Road Casualties Scotland is one of a series of Transport Statistics publications. Details of other Transport Scotland statistics can be found at http://www.transportscotland.gov.uk/analysis/statistics.

Key articles from previous editions of Reported Road Casualties Scotland
Article	Version of RRCS where article can be found
Estimating under- counting of Road Casualties in Scotland	RRCS 2010 http://bit.ly/2xSFW9v
Priorities in Scotland's Road Safety Framework to 2020- An assessment of relative levels and trends	RRCS 2011 http://bit.ly/2yHMoz6
Comparison of police casualty statistics with other sources	RRCS 2011 http://bit.ly/2yHMoz6
Vulnerable road users	RRCS 2014 http://bit.ly/2yqZLrx
In Focus: Pedal and motorcycle casualties	RRCS 2013 http://bit.ly/2yXQcxb
Road User Factsheet	RRCS 2017 https://bit.ly/2IVRkbl
Casualty rates for local authority roads by local authority area, and the likely range of random year-to-year variation in these figures	RRCS 2018 https://bit.ly/2SW0GZg

We welcome suggestions for improving the usefulness of the data and the publications. Comments and enquiries should be sent to the address overleaf.

Andrew Paterson
Statistician
Transport Statistics
Transport Scotland
Victoria Quay
Edinburgh EH6 6QQ
Telephone: 0131 244 3201
Email: Transtat@transport.gov.scot

Figure 1 - Reported accidents by severity 1966 to 2021

Note for Figure 1: Due to changes in the way casualty severities are recorded, figures for serious accidents prior to 2004 are not comparable with later years.

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