The Problem of the Comparability of Road Accident Data from Different European Countries

Round 1

Reviewer 1 Report

Comments and Suggestions for Authors

The paper presents a relevant investigation, emphasizing the need to have comparable road accident data across Europe.

However, several weaknesses should be addressed. First of all, the research lacks clearly articulated research questions or hypotheses, which weakens the methodological framing. The structure of the empirical section would benefit from a more coherent integration of the analysis into a formal research design, possibly including multivariate or cluster analysis to reinforce the findings. The discussion tends to overgeneralize conclusions without sufficiently exploring limitations, such as differences in national data collection systems, or cultural reporting behaviors.

In addition, the literature is mostly descriptive and should be improved through a rigorous methodology having in mind data harmonization and statistical validity.

As a general conclusion, the paper should propose a rigorous and replicable methodology for accident data collection, compare the existing data against it, and find strengths and weaknesses of each country's methodology. This would allow the authors to make actionable recommendations tailored to specific national contexts. Without such a framework, the paper remains primarily descriptive and lacks the analytical depth required to meaningfully contribute to improving the current situation.

Author Response

• However, several weaknesses should be addressed. First of all, the research lacks clearly articulated research questions or hypotheses, which weakens the methodological framing. The structure of the empirical section would benefit from a more coherent integration of the analysis into a formal research design, possibly including multivariate or cluster analysis to reinforce the findings. The discussion tends to overgeneralize conclusions without sufficiently exploring limitations, such as differences in national data collection systems, or cultural reporting behaviors.
  

  We concur with the reviewer that certain conclusions in our paper are presented in a concise and, perhaps, somewhat simplified manner. However, in discussing the definition of an injured person, our intention extends beyond the literal wording of the relevant footnote to encompass the broader data collection system.
  It is important to recognize that while the definition of an injured person may be objectively precise and theoretically sound, its application in practice is often inherently subjective.
  The aim of our article is to highlight the lack of data comparability and to emphasize that this is not a trivial issue leading merely to minor inaccuracies. The most critical aspect lies in the empirical examples - namely, the absence of correlation with fatality rates - which clearly demonstrate that analyses based on accident or injury data may result in fundamentally divergent, and therefore erroneous, conclusions.

• In addition, the literature is mostly descriptive and should be improved through a rigorous methodology having in mind data harmonization and statistical validity.

  The purpose of the literature review was not to provide or cite reliable international analyses based on information about the number of injuries and accidents, as doing so would contradict the conclusions of our article, which clearly state that such data must not be analyzed.
  The most critical part of the bibliography, as reflected in the discussion, consists primarily of examples of incorrect comparisons involving non-comparable data. Our intention is to highlight that such instances appear both in scholarly articles and in institutional reports issued by entities such as the United Nations, police authorities, and government agencies.

• As a general conclusion, the paper should propose a rigorous and replicable methodology for accident data collection, compare the existing data against it, and find strengths and weaknesses of each country's methodology. This would allow the authors to make actionable recommendations tailored to specific national contexts. Without such a framework, the paper remains primarily descriptive and lacks the analytical depth required to meaningfully contribute to improving the current situation.
  

  The objective of our article was to draw attention to the lack of comparability in data on the number of injuries (and, consequently, the number of accidents) across different countries - even within a relatively homogeneous group such as the European Union. This issue is particularly significant, as databases provided by Eurostat, the OECD, and many others present such information in consolidated files, which strongly suggests their comparability.
  The harmonization of data collection systems goes beyond the scope of our competencies; however, we appreciate this suggestion and, as individuals genuinely committed to the topic, we will consider forming a broader team to address this important issue.

Reviewer 2 Report

Comments and Suggestions for Authors

The topic of the paper addresses an important issue related to the challenges of comparing international road safety data across countries. The core argument of the paper is based on the lack of a harmonized definition of a road accident and an injured person across European countries. The authors highlight the incomparability of road safety data stemming from differing definitions of accidents, injuries, and fatalities at the national levels. While the authors present an interesting approach, certain sections lack the depth and complexity necessary for a comprehensive study. With improvements in methodology clarity, data visualization, and discussion depth, this paper could be an interesting contribution to the understanding of data comparability issues in road safety research.

Recommendations for Improving the Paper:

• Global perspective: What is the situation worldwide? It would be beneficial to consider this aspect and include at least its brief overview. Several of the references are related to the global road safety situation, and this should be better reflected in the discussion.
• Classification of injuries: The paper lacks differentiation between injuries and serious injuries, which are commonly used in classifications of accident consequences at both national and international levels. This distinction should be clarified and consistently applied.
• Time frame clarification: The authors state that the analysis covers the period from 1999 to 2022. They should explain why more recent data were not included in the analysis, particularly given that newer datasets are publicly available.
• Definitions of injured persons: In the section 3.4 "Reasons for discrepancies in data on accidents, injuries and fatalities," it would be highly beneficial to include definitions of injured persons for all countries analyzed—not only Poland, Germany, Hungary, and Austria. Alternatively, an explanation should be provided for why only these four countries were selected. It is strongly recommended to include a summary table comparing the definitions of “injured” across all analyzed countries to support the discussion on definitional discrepancies.
• Sources in figures: All figures in the paper are missing source citations. These should be included to ensure transparency and academic integrity.
• Lines 32 - 34: Provided statement is overly general and does not apply to all countries. Please be more specific.
• Line 193 - Figure 2: The authors should provide explanations for the information given in parentheses, e.g. in the form of legend.
• Lines 242 - 245: Is the definition of “fatal accident” the same across all countries analyzed? If so, since when? This is a crucial point and must be clarified with appropriate references. For example, France defined a fatality as a person who died within six days of the collision until 2005, after which the country adopted the 30-day standard to align with international practices. Variations like this can cause significant discrepancies in data reporting and must be addressed in the core argument. Are correction factors applied in countries that historically used shorter timeframes for defining road traffic fatalities, to adjust the data to a 30-day equivalent? This should be explained clearly.
• Line 280: The section title currently reads "3.5. Classification of the analysed countries according to the level of road safety from 1999 to 2002.” This appears to be a typo. It should read “from 1999 to 2022.
• Line 471: Source 4 refers to data available for the year 2021 ("Cause-specific mortality, 2000–2021"). Please explain why the reference year listed is 2023.

Redundant statements: The statement in lines 96–98 is repeated in lines 126–128. It is unnecessary to repeat the same information in such close text proximity.

References section: It is unclear why the authors are not referencing the most recent reports available on road safety: Source 5 refers to the ITF report from 2022, even though the latest report from 2024 is already available (ITF 2024). Source 8 references the EU report from 2022, while the Annual Statistical Report on Road Safety in the EU 2025 (European Commission, February 2025) is already published online. Source 56 cites a strategy document from 2012, even though the latest version is from 2019 ("Strategia Zrównoważonego Rozwoju Transportu do 2030 roku"). The older source should be replaced or supplemented with the newer one. Source 46 references the 2023 Road Safety Country Profile for Austria. It would be beneficial to also consider the 2024 update (Austria 2024 profile) and compare the findings.

Additional recommended sources of references: The paper would benefit from incorporating other key reports such as the Global Road Safety Facility 2024 report (World Bank). Another relevant source with DOI 10.2495/SDP240321 could be also considered by the authors, as it deals directly with the topic of paper.

 

Author Response

• Global perspective: What is the situation worldwide? It would be beneficial to consider this aspect and include at least its brief overview. Several of the references are related to the global road safety situation, and this should be better reflected in the discussion.
  

  We would like to note that during the submission process, we were advised to modify the title from "international analysis" to "analysis of European countries." Naturally, the bibliography includes references to publications addressing a broader scope. However, if data incomparability is evident within a relatively homogeneous group of EU countries, the issue will inevitably persist - and likely intensify - in any wider country group.
  To support this assertion with empirical evidence, we examined the consistency of rankings based on fatality and injury indicators across several dozen countries, including both European and non-European states.
  
  

• Classification of injuries: The paper lacks differentiation between injuries and serious injuries, which are commonly used in classifications of accident consequences at both national and international levels. This distinction should be clarified and consistently applied.
  

  We cannot agree with the reviewer’s comment regarding the widespread use of the distinction between injuries and serious injuries. While data on serious injuries can be found in selected reports of the European Union, it is absent from key statistical databases such as those maintained by Eurostat and the OECD. It is only natural that researchers conducting analyses rely primarily on accessible databases rather than searching for figures in fragmented reports. Moreover, harmonized data based on the MAIS3+ methodology is presented in the 2025 Annual Statistical Report on Road Safety in the EU for only 14 countries from 2022 and merely 6 countries from 2023 (pp. 14).

• Time frame clarification: The authors state that the analysis covers the period from 1999 to 2022. They should explain why more recent data were not included in the analysis, particularly given that newer datasets are publicly available.
  
  In line with the reviewer’s suggestion, the analysis was extended to include data from 2023, which completes the time frame of an entire quarter-century. Unfortunately, the 2025 Eurostat report does not contain any data from 2024 - as contrary to expectations, reports for a given year typically include data from two years prior. Likewise, according to the data available on 2 July 2025, the EUROSTAT and OECD databases contained no data whatsoever for 2024.
  
• Definitions of injured persons: In the section 3.4 "Reasons for discrepancies in data on accidents, injuries and fatalities," it would be highly beneficial to include definitions of injured persons for all countries analyzed - not only Poland, Germany, Hungary, and Austria. Alternatively, an explanation should be provided for why only these four countries were selected. It is strongly recommended to include a summary table comparing the definitions of “injured” across all analyzed countries to support the discussion on definitional discrepancies.
  

  The selection of countries was guided by the variation in injury rate levels. In particular, the rate in Germany was significantly higher than in Poland. The disparity in injury rates between countries suggested substantial differences in the definition of an injured person - which, as demonstrated by the definitions cited in the article, was indeed the case.
  The manuscript has been supplemented with information regarding definitional challenges, and a source has been provided that includes a comparative overview of definitions of serious accidents.
  Definitions of seriously injured persons are included, for example, in the document:
  [52] European Transport Safety Council, RANKING EU PROGRESS ON ROAD SAFETY. 18th Road Safety Performance Index (PIN) Report June 2024, pp. 60-63. https://etsc.eu/wp-content/uploads/ETSC-18th-PIN-Annual-Report-DIGITAL-V3.pdf

• Sources in figures: All figures in the paper are missing source citations. These should be included to ensure transparency and academic integrity.
  
  We appreciate the reviewer’s attention to this oversight. Source information has now been added beneath all figures.
  
  
• Lines 32 - 34: Provided statement is overly general and does not apply to all countries. Please be more specific.
  
  This statement has been clarified with respect to the time frame; the marked decline in the number of road traffic fatalities between 1999 and 2023 is evident across all countries. Random fluctuations resulting from the low number of fatalities in countries such as Malta and Liechtenstein have been excluded from consideration. A reference to Table 2, which presents detailed indicators for all countries, has been added in support of this statement.
  
  
• Line 193 - Figure 2: The authors should provide explanations for the information given in parentheses, e.g. in the form of legend.
  
  We appreciate the reviewer’s attention to this oversight. The appropriate clarification has now been added beneath the maps.
  
  
• Lines 242 - 245: Is the definition of “fatal accident” the same across all countries analyzed? If so, since when? This is a crucial point and must be clarified with appropriate references. For example, France defined a fatality as a person who died within six days of the collision until 2005, after which the country adopted the 30-day standard to align with international practices. Variations like this can cause significant discrepancies in data reporting and must be addressed in the core argument. Are correction factors applied in countries that historically used shorter timeframes for defining road traffic fatalities, to adjust the data to a 30-day equivalent? This should be explained clearly.
  
  Minor deviations from this definition were present in several countries, though these occurred in the past. Since the vast majority of fatalities involve individuals who die at the scene, such differences did not significantly affect data comparability. For over a decade now, the definition of a person killed in a traffic accident has been standardized. We therefore consider it unnecessary to include extensive detail on this matter, as it does not impact the majority of the data analyzed.
  
  
• Line 280: The section title currently reads "3.5. Classification of the analysed countries according to the level of road safety from 1999 to 2002.” This appears to be a typo. It should read “from 1999 to 2022".
  
  Indeed, this was an oversight. We appreciate the reviewer’s attention to this matter. The title has been corrected to “…1999–2023” in accordance with the recommendation to update the data.
  
  
• Line 471: Source 4 refers to data available for the year 2021 ("Cause-specific mortality, 2000–2021"). Please explain why the reference year listed is 2023.
  
  Indeed, this was a mistake. We appreciate the reviewer’s attention to this oversight. The correct link to the report has been provided: World Health Organization, Global status report on road safety 2023. Geneva, 2023, pp. 3.  https://iris.who.int/bitstream/handle/10665/375016/9789240086517-eng.pdf?sequence=1
  
  
• Redundant statements: The statement in lines 96–98 is repeated in lines 126–128. It is unnecessary to repeat the same information in such close text proximity.
  
  We appreciate the reviewer’s attention to this repetition. The statement in lines 96–98 has been removed.
  
  
• References section: It is unclear why the authors are not referencing the most recent reports available on road safety: Source 5 refers to the ITF report from 2022, even though the latest report from 2024 is already available (ITF 2024). Source 8 references the EU report from 2022, while the Annual Statistical Report on Road Safety in the EU 2025 (European Commission, February 2025) is already published online. Source 56 cites a strategy document from 2012, even though the latest version is from 2019 ("Strategia Zrównoważonego Rozwoju Transportu do 2030 roku"). The older source should be replaced or supplemented with the newer one. Source 46 references the 2023 Road Safety Country Profile for Austria. It would be beneficial to also consider the 2024 update (Austria 2024 profile) and compare the findings. The paper would benefit from incorporating other key reports such as the Global Road Safety Facility 2024 report (World Bank). Another relevant source with DOI 10.2495/SDP240321 could be also considered by the authors, as it deals directly with the topic of paper.
  

  We appreciate the reviewer’s observation regarding the absence of references to the most recent reports on road safety. Older sources have now been complemented with more recent ones. 

  [5] ITF, Road Safety Annual Report 2024, OECD Publishing, Paris, 2024,
  https://www.itf-oecd.org/sites/default/files/docs/irtad-road-safety-annual-report-2024.pdf.

  [9] European Commission, Annual statistical report on road safety in the EU, 2025. European Road Safety Observatory. Brussels, European Commission, Directorate General for Transport, 2025.  
  https://road-safety.transport.ec.europa.eu/document/download/17d70e9c-d9c4-4273-b497-41b61194e808_en?filename=ERSOnext_AnnualReport_20250227.pdf 

  [60] Rada Ministrów, Strategia Zrównoważonego Rozwoju Transportu do 2030 roku. Monitor Polski, 2019.  poz. 1054. https://www.gov.pl/web/infrastruktura/projekt-strategii-zrownowazonego-rozwoju-transportu-do-2030-roku2

  [48] European Commission, Country Profile Austria. Road Safety Observatory. Brussels, European Commission, Directorate General for Transport, 2023, https://road-safety.transport.ec.europa.eu/system/files/2024-01/erso-country-overview-2024-austria.pdf

  [66] Mikusova, M., Kyamakya, K., Gnap, J. Sustainable development through strategic road safety management: A regional approach. WIT Transactions on Ecology and the Environment, 2024, 262, 379–390. https://doi.org/10.2495/SDP240321

Round 2

Reviewer 2 Report

Comments and Suggestions for Authors

All my comments were taken into consideration by the authors and the paper was updated accordingly. Its overall quality improved significantly. After revising the layout issues and improving formatting of the paper according to the journal requirements I would be very happy to recommend it for publication.

Author Response

All my comments were taken into consideration by the authors and the paper was updated accordingly. Its overall quality improved significantly. After revising the layout issues and improving formatting of the paper according to the journal requirements I would be very happy to recommend it for publication.

Thank you for accepting our responses to your valuable comments, which allowed us to significantly improve our article.
Thank you also for your positive evaluation of our work.