Managing Innovation for a Sustainable Transport System: A Comparative Study of the EU and Ukraine

Round 1

Reviewer 1 Report

Comments and Suggestions for Authors

Please see the attached PDF file.

Comments for author File: Comments.pdf

Author Response

• Regarding originality and significance, the manuscript addresses a topical and under- explored nexus: the joint evolution of digitalization, environmental performance, and institutional resilience in EU and Ukrainian transport systems. The cross-sector perspective (freight rail, urban public transport, last-mile logistics) and the wartime context of Ukraine provide a distinctive empirical angle, and the attempt to derive lessons for mutual learning (EU learning from Ukraine’s crisis-driven agility; Ukraine learning from EU regulatory and reporting practices) is conceptually  How- ever, the contribution is currently more synthetic than analytical. The manuscript could better explain how its KPI-based framework advances existing comparative or benchmarking approaches in transport sustainability. As it stands, the claim that few studies integrate digital and environmental indicators into a harmonized framework is plausible but somewhat overstated; the authors should more systematically position their approach against existing indicator frameworks and comparative studies in EU and Eastern European transport, clarifying what is genuinely new beyond bringing existing KPIs together for this particular set of cases.

While individual indicator frameworks addressing digitalization or environmental performance in transport systems are well established, their systematic integration with institutional resilience into a single comparative KPI-based framework, which os applicable across both stable and crisis-affected governance contexts, remains limited. This limitation is mentioned in Methodology section.

• On methodology and data, the core design is a comparative, descriptive-analytical study using secondary data for a single year (2022) and six case operators.The choice of subsectors is reasonable and well justified, but the sampling strategy at the operator level and its implications for external validity require more critical  For example, DB Cargo and Ukrzaliznytsia are both dominant national players, but their business models, regulatory environments, and accounting practices differ sub- stantially; similarly, Angers versus Lviv and PostNL versus Nova Poshta represent particular municipal and corporate contexts. The manuscript should more clearly acknowledge that the generalization base is narrow and that results are illustrative rather than statistically representative.

Given the limited number of case operators and their context-specific business models and regulatory environments, the findings should be interpreted as illustrative and exploratory, providing analytical insights rather than statistically representative generalizations across transport systems. This point is also added as an important mention in the Methodology section.

• The KPI construction and estimation procedures are central to the paper and should be presented with more methodological rigor.The authors rely on several approx- imations, including estimating DB Cargo revenue from DB Group totals; deriving Ukrzaliznytsia’s tonne-kilometres from pre-war 2019 data and assuming a 15% reduc- tion in average haul length; and converting Ukrainian financial data using an annual average exchange rate. These choices are reasonable as first-order approximations but require more systematic justification, a clearer description of uncertainty ranges, and at least a brief sensitivity or robustness check to show that the main qualitative conclusions do not hinge on specific parameter assumptions. Otherwise, there is a risk that cross-company comparisons are artifacts of modeling choices rather than structural differences.

 

Several KPIs rely on first-order approximations due to data limitations. However, alternative parameter values were tested within plausible ranges, and the resulting variations do not affect the qualitative patterns or comparative conclusions reported in the study (which is also mentioned in Methodology section).

• The operationalization of digitalization and institutional resilience is a key weakness relative to the paper’s ambitions. Digitalization is described as a “descriptive status” with mostly yes/no indicators for mobile apps, tracking platforms, and IT initiatives, and there is no explicit digital maturity index or scoring rubric. Institutional resilience is introduced conceptually as the capacity to maintain functionality, adapt, and re- cover under crisis, but it is not linked to any quantitative proxies or coded qualitative indicators. As a result, the empirical analysis cannot convincingly “quantify the inter- section between digitalization, environmental efficiency and institutional resilience” as claimed in the conclusions. For a major revision, I would strongly encourage the authors to (a) define a small, transparent scoring scheme for digitalization maturity (e.g., 0-3 scale on several dimensions) and (b) either operationalize resilience using measurable proxies (e.g., continuity of service, speed of recovery, diversification of corridors) or explicitly reposition resilience as a qualitative interpretive lens instead of a component of the KPI framework.

 

Although institutional resilience is conceptually central to the analysis, it is not operationalized through synthetic scores or ordinal indices in this study. This decision reflects substantial cross-case heterogeneity in governance structures, crisis exposure, reporting practices, and data availability, which would render composite resilience scoring methodologically fragile and potentially misleading. Constructing synthetic or ordinal resilience measures would require strong assumptions regarding indicator selection, weighting, and functional equivalence across EU and Ukrainian operators—assumptions that cannot be robustly validated under wartime and post-crisis conditions. Instead, institutional resilience is employed as a qualitative analytical lens that contextualizes observed digitalization and environmental performance outcomes in terms of operational continuity, adaptive responses, and institutional capacity under stress. This approach prioritizes analytical validity and transparency over artificial quantification and reduces the risk that cross-case differences reflect modeling artifacts rather than substantive structural characteristics.

• Concerninganalysis and interpretation, the subsector-specific narratives (freight rail, urban public transport, last-mile logistics) are informative and provide a rich contextual description of EU and Ukrainian operators, including discussion of network structure, financial conditions, and wartime disruptions. However, the analytical techniques remain limited to pairwise comparisons of KPIs and qualitative  The paper would benefit from modest additional analysis, even within the constraints of a small sample, such as normalizing KPIs against broader sector benchmarks, providing simple ratio comparisons across all six operators in a single consolidated table, or framing the differences using a simple multi-criteria scoring or radar chart. Such additions could substantiate the statement that the study “quantifies specific performance gaps” rather than merely describing them.

To move beyond purely narrative comparison, the analysis consolidates key KPIs across all six operators into a unified comparative structure and applies simple normalization and ratio-based contrasts relative to subsector-specific reference values. While the limited sample size precludes advanced statistical techniques, this modest analytical extension allows relative performance gaps to be expressed in a transparent and comparable manner, thereby supporting a quantified interpretation of cross-operator differences without overstating precision or generalizability. An explanation is added to the Results section.

• Thesynthesis and policy recommendations are among the strengths, but could be sharp-  The cross-subsector synthesis section clearly articulates a structural asymmetry between mature EU governance architectures and reconstruction-oriented Ukrainian systems, and Table 4 provides differentiated recommendations for freight rail, urban transport, and last-mile logistics along several dimensions. To better align with the data, each recommendation should be explicitly tied to the observed KPI gaps; for example, if revenue per ton or CO₂ intensity differs by a particular factor, the recom- mendation should address that gap. In addition, the authors may consider prioritizing recommendations (short-term vs long-term, necessary vs desirable) and clarifying which actions are realistically implementable under current wartime and post-war funding constraints in Ukraine.

 

The recommendations are marked in the next way: “Short-term” (S), “Long-term” (L), “Critical” (C), “Optional” (O). The corresponded marks are added to Table 4. Recommendations for improving transport systems of EU and Ukraine

• Regarding structure, presentation, and language, the article is generally well organized, with a precise sectioning from literature review through methods, results, discussion, and conclusions. The literature review is up to date and clearly distinguishes among global conceptual work, EU empirical studies, and emerging Ukrainian research. It clearly identifies several research gaps that motivate the KPI framework. Some refinement is still needed: parts of the literature review are somewhat repetitive, and specific paragraphs could be streamlined to avoid duplicating findings. The writing is understandable primarily, but contains grammatical errors, non-idiomatic phrases (“f.e.”, “most probably the amount of residents has been expanded”), and occasional inconsistencies in tense and style. The manuscript would benefit from a thorough language edit by a proficient English speaker and a careful check against the journal’s formatting and referencing requirements.

The double check for a language edit has been done, with additional cleaning through the text of the paper.

• Finally, with respect to conclusions and implications, the closing section effectively reiteratesthe main sectoral  It emphasizes that digitalization and sustainability are mutually reinforcing only under conditions of coherent governance. This is a valuable message. To meet the journal’s high standards for conclusions, the authors should make the causal logic more explicit (i.e., by specifying the mechanisms that plausibly link the observed KPIs to governance structures) and delimit the scope of their claims. Explicitly acknowledging that the conclusions are based on a small set of case operators and a single year, and framing them as indicative patterns rather than definitive sector-wide generalizations, will increase credibility. The authors could also expand the discussion of future research directions, for example, by suggesting longi- tudinal studies across multiple years, broader operator samples, or mixed-methods designs combining KPI analysis with interviews or process tracing of digitalization initiatives.

Conclusions have been updated based on this comment.

Author Response File: Author Response.pdf

Reviewer 2 Report

Comments and Suggestions for Authors

This paper focuses on the differences in digitalization and sustainability as well as development recommendations in three major fields, namely freight rail, urban public transport, and last-mile postal logistics, between the EU and Ukraine. In terms of topic selection, it has clear engineering value and academic significance. Its overall structure is standardized, the research methodology is rigorous, and the logic of data extraction and synthesis is clear, providing valuable references for summarizing technologies in this field and clarifying future directions. However, there is still room for optimization in terms of content.

1.The core research object of this paper is the transport systems of the EU and Ukraine. Although it covers three major subsectors: freight rail, urban public transport, and last-mile postal logistics, it does not clearly explain why these three subsectors are chosen. It is necessary to supplement relevant literature or evidence for verification.

2. In the analysis of freight rail, when estimating the freight turnover of Ukrzaliznytsia in 2022, the assumption that "the average transport distance decreased by 15%" is made, but the basis for this assumption is not explained, and the rationality of the assumption lacks support. It is necessary to supplement relevant literature or evidence for verification.
3. When selecting EU cases, it does not explain why Germany (for freight rail), France (for urban public transport), and the Netherlands (for postal logistics) are chosen, nor does it illustrate the representativeness of these countries in the EU transport system.
4. For the assessment of the availability of digital IT online platforms, a "yes/no" qualitative judgment is adopted, and it is necessary to explain the reason for not using quantitative analysis.
5. In the second part, Santarius et al. argue that digitalisation represents a "double-edged sword", but the drawbacks of digitalization are not explained. At the same time, the limitations of data, methodology, and context are not reflected in the conclusion through reflection.
6. There are no figures in the paper. It is suggested to supplement some figures to facilitate readers' better understanding of the content.

Author Response

Review 2

 

This paper focuses on the differences in digitalization and sustainability as well as development recommendations in three major fields, namely freight rail, urban public transport, and last-mile postal logistics, between the EU and Ukraine. In terms of topic selection, it has clear engineering value and academic significance. Its overall structure is standardized, the research methodology is rigorous, and the logic of data extraction and synthesis is clear, providing valuable references for summarizing technologies in this field and clarifying future directions. However, there is still room for optimization in terms of content.

1.The core research object of this paper is the transport systems of the EU and Ukraine. Although it covers three major subsectors: freight rail, urban public transport, and last-mile postal logistics, it does not clearly explain why these three subsectors are chosen. It is necessary to supplement relevant literature or evidence for verification.

The selection of freight rail, urban public transport and last-mile postal logistics is grounded in both sustainability theory and transport policy practice. Together, these subsectors represent the core functional layers of contemporary transport systems: long-distance freight flows, collective passenger mobility and last-mile distribution. This structure closely aligns with the Avoid–Shift–Improve framework, widely applied in EU transport policy, where freight rail supports modal shift from road, urban public transport enables low-carbon passenger mobility, and last-mile logistics addresses the fastest-growing and most emission-intensive segment of urban transport. Previous studies emphasise that these three domains account for the majority of transport-related emissions while offering the highest potential for digital-enabled efficiency gains and decarbonisation. Analysing them jointly allows a system-level assessment of how digitalisation and sustainability interact across freight, passenger and consumer-facing transport layers.

Mobilizing the transport sector to tackle climate change | UNECE

ITF Transport Outlook 2021 | ITF

 

1. In the analysis of freight rail, when estimating the freight turnover of Ukrzaliznytsia in 2022, the assumption that "the average transport distance decreased by 15%" is made, but the basis for this assumption is not explained, and the rationality of the assumption lacks support. It is necessary to supplement relevant literature or evidence for verification.

 

 

The assumption of a 15% reduction in the average haul distance of Ukrzaliznytsia in 2022 is based on documented structural changes in Ukrainian freight corridors following the blockade of Black Sea ports. According to the EBRD and World Bank, a substantial share of bulk exports was redirected from long-distance east–south routes toward shorter westbound land corridors connecting Ukraine with EU border terminals. Pre-war average haul distances for Ukrainian bulk freight often exceeded 700–800 km, whereas rerouted land-based export flows typically ranged between 500 and 650 km. To reflect this shift conservatively, the analysis applies a 15% reduction scenario, which is consistent with international transport assessments and avoids overestimation of freight turnover. This approach follows established practices in transport economics when operator-level ton-kilometre data are unavailable.

 

Ukraine - Third Rapid Damage and Needs Assessment (RDNA3) : February 2022 - December 2023

 

 

2. When selecting EU cases, it does not explain why Germany (for freight rail), France (for urban public transport), and the Netherlands (for postal logistics) are chosen, nor does it illustrate the representativeness of these countries in the EU transport system.

Germany, France and the Netherlands were selected as EU case countries due to their structural representativeness and leadership within the European transport system. Germany hosts Europe’s largest rail freight market and Deutsche Bahn Cargo is the continent’s leading rail freight operator by tonne-kilometres, making it a natural benchmark for freight rail analysis. France represents a mature model of urban public transport governance, combining public ownership with performance-based management through operators such as RATP, widely referenced in EU mobility policy. The Netherlands is consistently ranked among Europe’s most advanced countries in sustainable and digital logistics, with PostNL recognised as a frontrunner in zero-emission last-mile delivery. Together, these cases capture advanced EU practices in freight, urban mobility and logistics, providing a robust comparative baseline for Ukraine.

 

 

Home - ITF 2023 Summit

Statistical pocketbook 2022 - Mobility and Transport - European Commission

 

3. For the assessment of the availability of digital IT online platforms, a "yes/no" qualitative judgment is adopted, and it is necessary to explain the reason for not using quantitative analysis.

 

The availability of digital IT online platforms was assessed using a binary (yes/no) indicator, reflecting the presence of a functional platform. This approach was adopted due to the lack of standardized, publicly available quantitative metrics and to ensure cross-case comparability.

 

 

4. In the second part, Santarius et al. argue that digitalisation represents a "double-edged sword", but the drawbacks of digitalization are not explained. At the same time, the limitations of data, methodology, and context are not reflected in the conclusion through reflection.

 

This study is subject to several limitations. First, it relies on secondary data, which varies in transparency and granularity between EU and Ukrainian operators. Second, several KPIs, particularly for Ukrainian companies, required scenario-based estimation due to data unavailability. Third, the qualitative assessment of digitalisation does not capture intensity or effectiveness. Finally, the wartime context limits the generalisability of Ukrainian results. These constraints underline the need for improved data disclosure and future research combining quantitative digitalisation indices with primary data.

 

Digitalization and Sustainability: A Call for a Digital Green Deal - ScienceDirect

 

 

 

5. There are no figures in the paper. It is suggested to supplement some figures to facilitate readers' better understanding of the content.

 

Not sure if figures are relevant for this paper. If this comment will become a blocker for the next possible round of reviews, I can think which figure can be added, but for this moment I don’t see a necessity for this.

 

Author Response File: Author Response.pdf

Reviewer 3 Report

Comments and Suggestions for Authors

Review

The article analyses sustainability and digitalisation in transport systems of the European Union and Ukraine. The authors examine three representative transport subsectors: freight rail transport, urban public transport, and last-mile postal logistics. The study employs a comparative, descriptive–analytical methodology based on secondary data derived from corporate sustainability reports, official statistical sources, and sectoral databases for the year 2022.

The article is structured into six chapters: Introduction, Literature Review, Materials and Methods, Results, Discussion, and Conclusions. The authors refer to a total of 49 literature sources.

Comments

General comments

The authors are to be commended for conducting a highly relevant and interesting study, which provides valuable insights into the comparison of transport activities under peacetime conditions in the EU and extraordinary wartime conditions in Ukraine. In effect, the authors analyse six systems—three operating under peacetime conditions and three under exceptional wartime conditions—and derive several noteworthy findings, despite the considerable difficulty of accessing data from the Ukrainian side during the ongoing war.

Nevertheless, I would like to draw attention to several comments outlined below.

Specific comments

Comment 1:
Table 1 and Table 2
In both tables, environmental indicators for Ukraine were not calculated, most likely due to wartime conditions. Consequently, comparisons in this respect should be avoided in the text for both freight rail transport and urban public transport.

Comment 2:
At several points in the manuscript, it is stated that the carbon footprint of freight transport by German railways is significantly lower than that of Ukrainian railways. This claim is not valid for the pre-war period. For example, in 2019, electricity generation in Ukraine consisted of 55% nuclear energy, 6% hydropower, and 2% solar and wind energy, while 37% was generated from coal, oil, and gas. This implies that 63% of electricity production in Ukraine originated from low-carbon sources that did not produce CO₂ emissions. Germany’s share of low-carbon electricity generation in 2019 was significantly lower (58%) and only reached a comparable level (63%) in 2024.

Furthermore, in 2019 Ukraine operated approximately 1,627 electric locomotives and 301 diesel locomotives, meaning that about 84% of trains were electrically powered. In the same year, Deutsche Bahn operated only 81% electric locomotives. Ukraine was also known for producing electricity for railway operations domestically through nuclear power plants, which reduced the need for importing expensive petroleum products, as consistently stated by Ukrainian transport experts.

Therefore, it should be emphasised that prior to the outbreak of the war, Ukrainian rail transport achieved better results in terms of a lower carbon footprint than German rail transport. During the war, due to the destruction of energy infrastructure, diesel traction in Ukraine has likely gained greater importance, which may have increased the carbon footprint; however, relevant data are currently unavailable.

Comment 3:
Chapter 4
Subsections should be numbered as follows:
4.1. Freight Rail Analysis
4.2. Urban Public Transport Analysis
4.3. Last-Mile Postal Logistics Analysis
4.4. Synthesis across Subsectors and Regions

Comment 4:
Page 7, Table 1
The title of Table 1 appears on page 7, whereas the table itself is located on page 8.

Comment 5:
Page 11
The heading Urban Public Transport Analysis appears on page 11, while the corresponding chapter starts on page 12. There is no blank space between the heading and the preceding text.

Comment 6:
Page 15
The heading Last-Mile Postal Logistics Analysis is barely noticeable. There is no blank space between the heading and the preceding text.

Comment 7:
Page 18
The heading Synthesis across Subsectors and Regions appears on page 18, while the corresponding chapter starts on page 19. There is no blank space between the heading and the preceding text.

 

Author Response

Review 3

The article analyses sustainability and digitalisation in transport systems of the European Union and Ukraine. The authors examine three representative transport subsectors: freight rail transport, urban public transport, and last-mile postal logistics. The study employs a comparative, descriptive–analytical methodology based on secondary data derived from corporate sustainability reports, official statistical sources, and sectoral databases for the year 2022.

The article is structured into six chapters: Introduction, Literature Review, Materials and Methods, Results, Discussion, and Conclusions. The authors refer to a total of 49 literature sources.

Comments

General comments

The authors are to be commended for conducting a highly relevant and interesting study, which provides valuable insights into the comparison of transport activities under peacetime conditions in the EU and extraordinary wartime conditions in Ukraine. In effect, the authors analyse six systems—three operating under peacetime conditions and three under exceptional wartime conditions—and derive several noteworthy findings, despite the considerable difficulty of accessing data from the Ukrainian side during the ongoing war.

Nevertheless, I would like to draw attention to several comments outlined below.

Specific comments

Comment 1:
Table 1 and Table 2
In both tables, environmental indicators for Ukraine were not calculated, most likely due to wartime conditions. Consequently, comparisons in this respect should be avoided in the text for both freight rail transport and urban public transport.

Due to the absence of consistent and publicly available environmental indicators for Ukrainian operators in 2022, particularly under wartime conditions, direct quantitative comparisons of CO₂ performance between EU and Ukrainian cases are avoided. For Ukraine, environmental performance is therefore discussed qualitatively and contextually, rather than through direct KPI benchmarking.

Comment 2:
At several points in the manuscript, it is stated that the carbon footprint of freight transport by German railways is significantly lower than that of Ukrainian railways. This claim is not valid for the pre-war period. For example, in 2019, electricity generation in Ukraine consisted of 55% nuclear energy, 6% hydropower, and 2% solar and wind energy, while 37% was generated from coal, oil, and gas. This implies that 63% of electricity production in Ukraine originated from low-carbon sources that did not produce CO₂ emissions. Germany’s share of low-carbon electricity generation in 2019 was significantly lower (58%) and only reached a comparable level (63%) in 2024.

Furthermore, in 2019 Ukraine operated approximately 1,627 electric locomotives and 301 diesel locomotives, meaning that about 84% of trains were electrically powered. In the same year, Deutsche Bahn operated only 81% electric locomotives. Ukraine was also known for producing electricity for railway operations domestically through nuclear power plants, which reduced the need for importing expensive petroleum products, as consistently stated by Ukrainian transport experts.

Therefore, it should be emphasised that prior to the outbreak of the war, Ukrainian rail transport achieved better results in terms of a lower carbon footprint than German rail transport. During the war, due to the destruction of energy infrastructure, diesel traction in Ukraine has likely gained greater importance, which may have increased the carbon footprint; however, relevant data are currently unavailable.

It is important to distinguish between the pre-war and wartime environmental performance of Ukrainian rail transport. Prior to 2022, Ukraine’s electricity mix consisted predominantly of low-carbon sources, with approximately 55% nuclear, 6% hydropower and 2% solar and wind energy, resulting in around 63% low-carbon electricity generation. In the same period, Germany’s share of low-carbon electricity was lower and reached a comparable level only after 2023. Moreover, in 2019, approximately 84% of Ukrainian locomotives were electric, compared to about 81% in Germany. Ukrainian railways also benefited from domestically produced nuclear electricity, reducing dependence on imported fossil fuels. Consequently, before the outbreak of the war, Ukrainian rail transport likely achieved a lower or at least comparable carbon footprint per tonne-kilometre than German rail transport. During the war, the destruction of energy infrastructure and increased reliance on diesel traction may have worsened this performance; however, due to the absence of verified data, this effect cannot be quantified and is discussed only qualitatively.

 

Comment 3:
Chapter 4
Subsections should be numbered as follows:
4.1. Freight Rail Analysis
4.2. Urban Public Transport Analysis
4.3. Last-Mile Postal Logistics Analysis
4.4. Synthesis across Subsectors and Regions

What we have in the paper:

1. Introduction
2. Materials and Methods
3. Results
   • 1. Freight Rail Analysis
   • 2. Urban Public Transport Analysis
   • 3. Last-Mile Postal Logistics Analysis
   • 4. Synthesis across Subsectors and Regions
4. Discussion
5. Conclusions

Comment 4:
Page 7, Table 1
The title of Table 1 appears on page 7, whereas the table itself is located on page 8.

Most probably something broken on the reviewers side. We checked the paper, filled in the journal's template as we uploaded it initially, and Table 1 is fully presented on page 6 (6 of 28).

Comment 5:
Page 11
The heading Urban Public Transport Analysis appears on page 11, while the corresponding chapter starts on page 12. There is no blank space between the heading and the preceding text.

Changed location of the text, to have the Table 2 fully on the page 11.

Comment 6:
Page 15
The heading Last-Mile Postal Logistics Analysis is barely noticeable. There is no blank space between the heading and the preceding text.

Added one more blank row, but not sure it is needed, since other tables also have just 1 blank row, while  Last-Mile Postal Logistics Analysis now has 2 blank rows.

Comment 7:
Page 18
The heading Synthesis across Subsectors and Regions appears on page 18, while the corresponding chapter starts on page 19. There is no blank space between the heading and the preceding text.

Like the previous comment, added one more blank row, just for sure.

 

 

 

 

Round 2

Reviewer 1 Report

Comments and Suggestions for Authors

The authors have adequately addressed the comments.

Author Response

Dear Reviewer,

Thank you very much for your review: comments and recommendations. We've taken your comments into account. The latest version of the article has been uploaded.

Best regards,

Authors

Author Response File: Author Response.pdf

Reviewer 2 Report

Comments and Suggestions for Authors

The authors have amended the paper accordingly. However, there is still room for optimization in terms of content.

1. The fourth row of Table 2 and the third row of Table 3 lack comments; it is recommended to supplement them.
2. The abbreviation "EU" first appears in Section 3.1, which is inconsistent with academic writing conventions—abbreviations should be introduced with their full names upon first occurrence in the paper, not in a later section. Please apply this revision to all other abbreviations (i.e., provide the full name followed by the abbreviation when first mentioned).
3. The formats of [24;25] in Line 383 and [27-28] in Line 414 are inconsistent and need to be modified in accordance with the journal's formatting requirements.

Author Response

Dear Reviewer, 

Thank you very much. We've taken your comments into account. The latest version of the article has been uploaded.

Best regards,

Authors

Author Response File: Author Response.pdf