Reported road casualties in Great Britain, provisional estimates involving illegal alcohol levels: 2020
Published 23 February 2022
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The recent trends in reported road casualties have been impacted by the national restrictions implemented from March 2020 onwards following the coronavirus (COVID-19) pandemic. More information can be found here in our release The impact of lockdown on reported road casualties in Great Britain.
About this release
This publication presents provisional estimates of casualties arising from reported accidents involving at least one motor vehicle driver or rider over the legal alcohol limit for driving, in Great Britain in 2020. Figures are derived from the STATS19 forms completed by the police plus toxicology data for road fatalities from coroners and procurators fiscal. Final 2020 estimates based on more complete data will be published in July 2022.
Main points
Provisional estimates for 2020 show that between 190 and 250 people were killed in accidents in Great Britain where at least one driver was over the drink-drive limit, with a central estimate of 220 deaths.
The provisional estimate of fatalities for 2020 is broadly in line with the last few years, and the reduction from 2019 is not statistically significantly different at the 95% confidence level.
The central estimate of 220 deaths is the lowest since 2015, though the overall number of reported road accidents also fell in 2020 as a result of the impact of the coronavirus (COVID-19) pandemic, so that drink-drive deaths were a higher percentage of the total than in the previous year.
The confidence intervals shown in Chart 1 are wider than usual due to lower number of fatalities in reported road accidents in 2020.
Chart 1: Fatalities in reported drink-drive accidents: GB, 2010 to 2020; error bars show 95% confidence intervals
In 2020, the estimated number of killed or seriously injured (KSI) casualties in accidents where at least one driver was over the alcohol limit decreased by 22% to 1,500 from 2019, the lowest number recorded.
An estimated 6,480 people were killed or injured when at least one driver was over the drink-drive limit. This represents a fall of 17% from 7,800 in 2019 and is also the lowest figure recorded.
The total number of accidents where at least one driver was over the alcohol limit decreased by 14% to 4,620 in 2020, the lowest number of drink-drive accidents recorded.
It is important to note that the number of reported drink-drive accidents and casualties involved in them is likely to have been impacted by the COVID-19 pandemic in 2020 and the national restrictions implemented from March 2020 onwards leading to a reduction in traffic and accidents. The falls in drink-drive accidents between 2019 and 2020 are broadly in line with the reduction in overall road accidents over the same period.
Casualties in drink-drive accidents in 2020
Drink-drive fatalities
These statistics, especially the number of fatalities, are subject to considerable uncertainty (see sampling uncertainty below). This means that it is impossible to be sure of the precise number of fatalities, so ranges and confidence intervals are used for fatalities throughout the publication.
The 95% confidence level is the standard against which statistics are typically tested. The bars on chart 1 are ranges of values for an estimate which we are 95% confident that the ‘true’ value falls in. Technically, it indicates that in 100 years with the same risk of fatalities (or injury), 95 of those years will result in a number of fatalities (or injuries) between a given range.
When we compare figures for the latest year with the previous year, we say that a change is ‘statistically significant’ if we are sufficiently confident (at the chosen level – here, 95%), based on the data available, that the difference between the 2 figures is the result of a genuine change, rather than being a product of chance - broadly, this is when the 2 sets of bars on Chart 1 don’t overlap. Otherwise, we say the change is ‘not statistically significant’ – this does not necessarily mean that there is not a genuine change, but that we are not able to determine one exists from the data available, at the chosen level of confidence.
The provisional central estimate of the number of deaths in accidents with at least 1 driver over the alcohol limit for 2020 is 220. This represents about 15% of all deaths in reported road accidents in 2020. The central estimate for 2020 is lower than the final figure for 2019, but the decrease is not statistically significant. The 95% confidence range indicates that we can be 95% confident that the true figure is between 190 and 250 fatalities.
The final estimate for 2020 is based on coroners’ and procurators’ fiscal reports for 52% of the drivers or riders who were killed in road traffic accidents in that year in addition to breath tests taken at the scene where the driver was not killed (see definitions below).
The prevalence of drink-driving in road deaths has fallen over time. In 1979, 26% of road deaths occurred in accidents where at least one driver or rider was over the drink-drive limit. This had fallen to 15% by 1989. Since then the percentage of road deaths that are drink-drive related has varied between 12% and 18%. In 2020, the rate was 15%.
Chart 2: Fatalities in reported drink-drive accidents, as a percentage of all fatalities: GB, 1979 to 2020
Drink-drive killed or seriously injured (KSI) casualties
The central estimate of the number of killed or seriously injured (KSI adjusted) drink-drive casualties in 2020 is 1,500, a decrease of 22% on 2019. This is the lowest level recorded.
For details on adjustments for non-fatal casualties see the ‘changes in systems for severity reporting’ section below.
Chart 3: Killed or seriously injured (KSI adjusted) casualties in reported drink-drive accidents: GB, 2010 to 2020
The proportion of killed or seriously injured (KSI adjusted) casualties in drink-drive accidents has varied between 5% and 7% since 2005. In 2020, the rate was 6%.
Chart 4: Killed or seriously injured (adjusted) casualties (KSI) in reported drink-drive accidents, as a percentage of KSI casualties: GB, 2005 to 2020
All drink-drive casualties
The central estimate of the number of drink-drive casualties of all severities in 2020 is 6,480, a fall of 17% from 7,800 in 2019. This is the lowest level recorded.
Chart 5: Total casualties in reported drink-drive accidents: GB, 2010 to 2020
It is estimated that around 6% of all casualties in reported road accidents in 2020 were involved in accidents in which at least one driver or rider was over the drink-drive limit.
In 1979, 9% of road casualties occurred in accidents in which at least one driver or rider was over the drink-drive limit. This has fallen to 5% by 1992 and has mainly varied around 5% since then.
Chart 6: Casualties in reported drink-drive accidents, as a percentage of all casualties: GB, 1979 to 2020
Number of drink-drive accidents in 2020
Trends in drink-drive accidents are similar to those for casualties.
There were an estimated 200 fatal drink-drive accidents in 2020, the lowest number since 2015.
The total number of drink-drive accidents of all severities fell by 14% to 4,620 from 2019 to 2020, the lowest number recorded. This means that around 5% of all reported road traffic accidents in 2020 involved at least one driver or rider over the legal alcohol limit.
In 1979, 8% of reported road accidents were drink-drive related. This fell to 5% by 1990 and has generally been around 5% since then.
It is important to note that the number of overall road traffic accidents has fallen, from 254,967 in 1979 to 91,199 in 2020, a 64% reduction. However, drink-drive accidents have fallen further; down 76% since 1979. It is therefore likely that some drink-drive initiatives have been effective in reducing the number of drink-drive accidents.
Chart 7: Reported accidents and drink-drive accidents: GB 1979 to 2020 (index 1979 = 100)
Background information
Tables published with this release
With this release, the headline table on drink-driving, RAS51001, has been updated with provisional 2020 figures. It shows accidents and casualties by severity since 1979. The final update for 2020 will be published in July 2022.
Proposed changes to tables issued with final drink-drive estimates
We are proposing to change the format of the drink-drive tables in July’s release to streamline them and make them accessible. Details of the proposed changes and accompanying feedback questionnaire is available and we would appreciate any feedback.
Definitions used throughout this publication
Drink-drive accident: A reported incident on a public road in which someone is killed or injured, where at least one of the motor vehicle drivers or riders involved met one of these criteria:
-
failed a roadside breath test by registering above 35 micrograms of alcohol per 100ml of breath (in England and Wales) or 22 micrograms (in Scotland)
-
refused to give a breath test specimen when requested by the police (other than when incapable of doing so for medical reasons).
-
died, within 12 hours of the accident, and was subsequently found to have more than 80 milligrams of alcohol per 100ml of blood (in England and Wales) or 50 milligrams (in Scotland).
Drink-drive casualties: All road users killed or injured in drink-drive accidents.
A full list of the casualty definitions used in this release is available.
Reviewing the frequency and improving the timeliness of drink-drive estimates
We want to further improve the quality and timeliness of road safety data. Currently, provisional drink-drive estimates are released 14 months after the end of the year reported on (with a return rate around 30% from coroners), and final estimates are released 20 months after the end of the year (with a return rate around 60% from coroners).
The return rates at the final stage for the last four years are as follows:
- 2016: 83%
- 2017: 86%
- 2018: 87%
- 2019: 80%
The figure for the latest year 2019 is lower than previous years due to the COVID-19 pandemic. We aim to increase the return rate post-pandemic.
We are looking to review the frequency and timeliness of drink-drive publications. Details of our proposed changes are available and we would welcome feedback on these.
Drug-driving statistics
The road safety team is currently exploring the feasibility of producing initial statistics on drug-driving from the same coroners data which forms part of these drink-drive statistics. We published initial analysis of deceased drivers who had more than the legal amount of drugs (illegal or medicinal) as a feasibility study. We would welcome feedback on the approach we are taking.
National Statistics
National Statistics are produced to high professional standards as set out in the Code of Practice for Statistics. They undergo quality assurance reviews to ensure that they meet customer needs. The statistics were last assessed during 2013 and the report number 258, is available.
Details of Ministers and officials who receive pre-release access to these statistics up to 24 hours before release are available.
Background on legislation
The Road Safety Act 1967 introduced the first drink-driving limit in the UK, set at a maximum blood alcohol concentration of 80mg of alcohol per 100ml of blood (or the equivalent 107mg of alcohol per 100ml of urine). It became an offence to drive, attempt to drive or be in charge of a motor vehicle on a road or other public place with a BAC that exceeded the maximum prescribed legal limit. The 1967 Act also made it an offence to fail to provide a specimen for a laboratory test without reasonable excuse.
The Transport Act 1981 introduced evidential breath testing and established a maximum breath alcohol concentration of 35 micrograms of alcohol in 100ml of breath. This was implemented in 1983. Today, people are given a preliminary breath test at the roadside and then taken back to the police station for an evidential breath test.
Drink-driving legislation has been strengthened over the years, including tougher penalties for offenders which can include potentially unlimited fines, disqualification from driving, or facing imprisonment for the most serious offences.
On 5 December 2014, Scotland reduced the legal BAC limit for all drivers from 80mg/100ml of blood to 50mg/100ml. The drink drive limit introduced by the 1967 Act remains in place for England and Wales today.
Evaluation of changes to the drink-drive limit
An independent evaluation of the impact of the limit reduction in Scotland led by the University of Glasgow was published in the Lancet on 12 December 2018. This evaluation took advantage of the natural experiment created by the lowering of the legal blood alcohol limit in Scotland only and compared data on weekly road traffic accident rates and alcohol consumption (off and on sales data) between Scotland (the intervention group) and England and Wales (the control group). The study found that lowering the drink-drive limit was not associated with any reduction in total accident rates or serious and fatal accident rates, but that the change was associated with a small reduction in per-capita alcohol consumption from on trade alcohol sales.
Quality and methodology
How do final estimates differ from the provisional estimates?
The final estimates have a narrower range than the provisional estimates. This is because the final estimates are based on more toxicology reports from coroners and procurators fiscal.
The main changes between the provisional and final estimates are for fatalities. This is because the data for fatal drink-driver accidents comes predominately from the toxicology reports while non-fatal drink-drive accidents data is derived mainly from breath test data. Breath test data is complete when the provisional estimates are published.
The provisional estimate of the number of fatalities in drink-drive accidents has usually been higher than the final estimate in recent years, as the table below shows. We are considering whether to combine the provisional and final publications into one release in future. We would request your feedback on this proposal using the contact details below.
Table 1: Estimated number of drink-drive fatalities at provisional and final stage, GB: 2015 to 2020
| Year | Final estimate | Provisional estimate |
|---|---|---|
| 2020 | 220 | |
| 2019 | 230 | 280 |
| 2018 | 240 | 240 |
| 2017 | 250 | 290 |
| 2016 | 230 | 240 |
| 2015 | 200 | 220 |
Sampling uncertainty
Toxicology data are not available for all killed drivers or riders recorded in STATS19 and are typically available for around 60% to 70% of relevant cases for final estimates. Provisional estimates for 2020 are based on 39% of relevant cases.
To account for the killed drivers without a known Blood Alcohol Content (BAC), the casualties from the known cases are scaled up. The estimates are therefore based on a sample, rather than a complete count, which introduces an element of uncertainty.
Due to the nature of the data used to create these estimates, there is considerably more uncertainty in the number of fatalities and fatal accidents than any other severity level. The reason for this is that 52% of fatalities in 2020 were motor vehicle drivers themselves.
Under-reporting of road casualties
The estimates in this release are based only on those road accidents which are reported to the police. Comparisons of road accident reports with death registrations show that very few, if any, road accident fatalities are not reported to the police. However, it has long been known that a considerable proportion of non-fatal casualties are not known to the police. The data used as the basis for these statistics are therefore not a complete record of all personal injury road accidents, and this should be borne in mind when using and analysing the figures.
Changes in systems for severity reporting
Non-fatal casualties since 2016 have been affected by a large number of police forces changing their reporting systems which has had a large impact on the classification of injuries recorded. Further details are in the guide to severity adjustments.
Methodology details
A methodology note is available describing how the drink-drive estimates are compiled from the sources.
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Contact details
Road safety statistics