Resource Intensity in the Japanese Transportation System: Integration of Vehicle and Infrastructure

Round 1

Reviewer 1 Report

Comments and Suggestions for Authors

This manuscript “Resource intensity in the Japanese transportation system: Integration of vehicle and infrastructure” has investigated resource efficiency in the form of resource intensity of transportation system by combining transportation means and infrastructure. This paper lacks innovation and the manuscript has some major defects. Thus, I suggest that the paper be major revision.

Q1: The authors must highlight their own findings from literature review.

Q2:There are a lot of abbreviations in the article, and the full names are not indicated, such as ICEV, HEV. It is necessary for the author to add a nomenclature at the beginning or end of the article. In the Abstract, the Reference should be avoided as much as possible.

Q3:The innovation of the article should be revised. The research background of internal combustion engines should be introduced in detail. Some references should be added and considered such as Energy 2024,292:130474. Please specify the real contribution of fuels in diesel engine.

Q4: In section 4, can the author consider the impact of factors such as season and temperature on vehicles?

Q5: The Fig. 1 should be improved, further explain it.

Q6: In the section 3, the transportation modes should be further explained. Why is transportation modes selected?

Q7: In the paper, Authors should try to avoid using the first person as much as possible, such as me, our, we, us. For example,

“Our framework suggests that existing studies lack an important part of infrastructure…”.

The author should be improved.

Author Response

Q1: The authors must highlight their own findings from literature review.

Thank you for your informative comment. To clarify the research gap, objective and contribution of this study, the introduction was revised as follows:
“A primary limitation of prior research examining resource use within the transport system lies in the restricted scope of system boundaries employed for re-source accounting. While direct material weight has been frequently utilized to assess resource use for transport infrastructure development, this approach presents chal-lenges in accurately estimating the practical environmental impact. Given that the ma-jority of resources are extracted through mining activities, and considering the docu-mented negative environmental [25] and biodiversity [26] impacts associated with these operations, the explicit consideration of mining activity volume is crucial for in-formed resource management discourse. The increasing extraction of natural resources via mining poses a substantial threat to the long-term sustainability of resources es-sential for the global energy transition [25]. Therefore, the volume of resource use, as viewed from the perspective of mining activity, should be adopted as a key indicator.
Limited scholarly attention has been directed towards analyzing resource utiliza-tion within the transportation sector from a mining perspective. While studies such as Takimoto et al., [28] and Watari et al., [25] have identified substantial increases in mining demand driven by the automotive industry, based on the mining intensity of various vehicle types [29], a gap remains in the literature. Even within the automotive sector, resource use associated with infrastructure development has received scant analysis. Furthermore, other crucial transportation modes, including railways, water-ways, and aviation, have been largely overlooked. This omission precludes a compre-hensive comparative analysis of different transportation modalities that considers both vehicle production and infrastructure requirements. Consequently, this study aims to develop a standardized classification framework for transport infrastructure, enabling comparisons across diverse transportation modes. Subsequently, by integrating trans-portation means with their associated infrastructure (roadways, railways, aviation, and waterways), the research will estimate the resource efficiency of the transportation system from a mining demand perspective. The contributions of this study are two-fold: (1) the provision of a standardized transport infrastructure framework for inter-modal comparison, applicable also to the analysis of other environmental indicators within the transport system; and (2) the identification of the most resource-efficient transportation mode, considering mining activity, through the integrated assessment of both vehicle and infrastructure.”

 

Q2:There are a lot of abbreviations in the article, and the full names are not indicated, such as ICEV, HEV. It is necessary for the author to add a nomenclature at the beginning or end of the article. In the Abstract, the Reference should be avoided as much as possible.

Thank you for your comment.
The reference was removed from the Abstract.
As suggested, the nomenclature was provided at the end of manuscript.

 

Q3:The innovation of the article should be revised. The research background of internal combustion engines should be introduced in detail. Some references should be added and considered such as Energy 2024,292:130474. Please specify the real contribution of fuels in diesel engine.

Thank you for your comment. As pointed out, an analysis of a specific feature of new ICEV technology (like diesel-hydrogen blended vehicle) is important, however, that is an out of scope in this study, in which the overall transportation mode is a subject of study. For your information, the analysis of mining intensity of such a new fuel vehicle is now under working and the suggested reference will be significantly helpful for discussion. I appreciated your kindness for sharing the knowledge.

 

Q4: In section 4, can the author consider the impact of factors such as season and temperature on vehicles?

Thank you for your comment. The raw data of this study is based on the statistical meta data, which means that such variations are already included as an average data. The lifecycle approach was applied here, so the specific factors such as season and temperature were difficult to be used to conduct the analysis. It might be possible to connect such a variation to the LCA, but it is out of scope of this study.

 

Q5: The Fig. 1 should be improved, further explain it.

Thank you for your comment. The explanation was added in the Fig title.

 

Q6: In the section 3, the transportation modes should be further explained. Why is transportation modes selected?

Basically, there are four transportation modes in this society (roadways, railways, aviation, waterways)
“in the four transportation modes (roadways, railways, aviation, waterways)” was newly added in the title of Fig. 3.

 

Q7: In the paper, Authors should try to avoid using the first person as much as possible, such as me, our, we, us. For example,
“Our framework suggests that existing studies lack an important part of infrastructure…”.
The author should be improved.

Thank you for your suggestions. As pointed out, such a description was removed accordingly.

Reviewer 2 Report

Comments and Suggestions for Authors

This research tries to develop an estimation framework for the resource intensity of transportation systems, which uses the Japanese case as an example.

Though the authors have completed their estimation, I don't find the contributions of their framework. The estimation method is simple and superficial. Although this estimation is processed at a microscope level, the characteristics of each transportation mode should be considered, such as the vehicle type, the traveling speed, the power generation methods, etc. The details of the calibration process for each parameter should also be given for a better understanding of the proposed models. In the meantime, I don't find the contributions of the proposed method.

Comments on the Quality of English Language

The English expression and wording can be further improved, which are a little bit difficult to understand. This paper will be beneficial to be proofread by a native English speaker. 

Author Response

Thank you for your informative comment. To clarify the research gap, objective and contribution of this study, the introduction was revised as follows:

“A primary limitation of prior research examining resource use within the transport system lies in the restricted scope of system boundaries employed for re-source accounting. While direct material weight has been frequently utilized to assess resource use for transport infrastructure development, this approach presents chal-lenges in accurately estimating the practical environmental impact. Given that the ma-jority of resources are extracted through mining activities, and considering the docu-mented negative environmental [25] and biodiversity [26] impacts associated with these operations, the explicit consideration of mining activity volume is crucial for in-formed resource management discourse. The increasing extraction of natural resources via mining poses a substantial threat to the long-term sustainability of resources es-sential for the global energy transition [25]. Therefore, the volume of resource use, as viewed from the perspective of mining activity, should be adopted as a key indicator.

Limited scholarly attention has been directed towards analyzing resource utiliza-tion within the transportation sector from a mining perspective. While studies such as Takimoto et al., [28] and Watari et al., [25] have identified substantial increases in mining demand driven by the automotive industry, based on the mining intensity of various vehicle types [29], a gap remains in the literature. Even within the automotive sector, resource use associated with infrastructure development has received scant analysis. Furthermore, other crucial transportation modes, including railways, water-ways, and aviation, have been largely overlooked. This omission precludes a compre-hensive comparative analysis of different transportation modalities that considers both vehicle production and infrastructure requirements. Consequently, this study aims to develop a standardized classification framework for transport infrastructure, enabling comparisons across diverse transportation modes. Subsequently, by integrating trans-portation means with their associated infrastructure (roadways, railways, aviation, and waterways), the research will estimate the resource efficiency of the transportation system from a mining demand perspective. The contributions of this study are two-fold: (1) the provision of a standardized transport infrastructure framework for inter-modal comparison, applicable also to the analysis of other environmental indicators within the transport system; and (2) the identification of the most resource-efficient transportation mode, considering mining activity, through the integrated assessment of both vehicle and infrastructure.”

Reviewer 3 Report

Comments and Suggestions for Authors

This paper investigates teh resource intensity in the Japanese transportation system integrating vehicle and infrastructure. Though a lot of work have been done, there are still some issues that should be addressed. Some suggestions and concerns are as follows:

1. The authors are recommended to re-organize the Introduction. Currently, the content in Introduction is somewhat stacked without logical continuity. Too many paragraphs are listed, but the relationship between different paragraphs are not clear. In fact, the authors should give the research background, existing problems and etc., and summarize the core contributions of this work.

2. Personally, there are a large amount of related literature published in the last three years. It would be better for the authors to cite more up-to-date references in the manuscript. 

3. What are the core contributions of this paper? In reviewing the paper, it can be found that the main indicator, i.e., TMR is from a reference, and the equations are already-existed. What methodologies or algorithms have been proposed by the authors?

4. Is there any comparison? In general, an academic paper, especially in the filed of science and technology, the authors should compare the proposed/adopted method with some baselines, proving the superiority of the proposed one. However, I did not find the corresponding part in this paper. Why?

5. The quality of figures in this paper is not satisfactory. For example, figures in Fig. 4 are blurry. Revise them.

6. When reviewing the paper, I was wondering what are the scientific problems behind the research? I must admit that the authors indeed conducted some work, but I failed to get the significance of this work.

Overall, I can not recommend the paper for publication in its current form, and a round of major revision is required.

Author Response

1. The authors are recommended to re-organize the Introduction. Currently, the content in Introduction is somewhat stacked without logical continuity. Too many paragraphs are listed, but the relationship between different paragraphs are not clear. In fact, the authors should give the research background, existing problems and etc., and summarize the core contributions of this work.

 

Thank you for your comment. Introduction was revised. Especially, the contribution of this study was newly added as follows:

“The contributions of this study are twofold: (1) the provision of a standardized transport infrastructure framework for intermodal comparison, applicable also to the analysis of other environmental indicators within the transport system; and (2) the identification of the most resource-efficient transportation mode, considering mining activity, through the integrated assessment of both vehicle and infrastructure.”

 

2. Personally, there are a large amount of related literature published in the last three years. It would be better for the authors to cite more up-to-date references in the manuscript. 

 

Thank you for your comment. The resource use of transportation system has seldom analyzed so far from the mining activity. Thus, the recent study relevant mining activity and transport is newly added as reference (e.g., Watari (2021), Takimoto (2024), Werner (2020))

 

3. What are the core contributions of this paper? In reviewing the paper, it can be found that the main indicator, i.e., TMR is from a reference, and the equations are already-existed. What methodologies or algorithms have been proposed by the authors?

 

Thank you for your comment. The TMR has been applied only to the automobile in the roadways. However, the transportation infrastructure in the roadway was never considered. Besides this, other transportation modes such as railway, waterway, and aviation have never been considered. The developed indicators so far were applied to those missing parts in the transportation system, that is different from existing studies. The following sentences were added in Introduction.

“Limited scholarly attention has been directed towards analyzing resource utiliza-tion within the transportation sector from a mining perspective. While studies such as Takimoto et al., [28] and Watari et al., [25] have identified substantial increases in mining demand driven by the automotive industry, based on the mining intensity of various vehicle types [29], a gap remains in the literature. Even within the automotive sector, resource use associated with infrastructure development has received scant analysis. Furthermore, other crucial transportation modes, including railways, water-ways, and aviation, have been largely overlooked.”

 

 

4. Is there any comparison? In general, an academic paper, especially in the filed of science and technology, the authors should compare the proposed/adopted method with some baselines, proving the superiority of the proposed one. However, I did not find the corresponding part in this paper. Why?

 

Thank you for your comment. As presented in Introduction, the objective of this study is to estimate the resource use of different transportation modes from the mining perspective, which have hardly been considered so far. The indicator called total material requirement (TMR) used in this study was used. If there were studies using different indicators which can evaluate the impact of mining impact, it would be possible to compare the results of this study with other indicators. However, as noted, there are no such studies. Considering this comment, it is future research which conducts the resource use estimation by using the different indicators to compare the result of TMR.

 

5. The quality of figures in this paper is not satisfactory. For example, figures in Fig. 4 are blurry. Revise them.

 

Thank you for your comment. We newly added the explanation in the Fig title.

 

6. When reviewing the paper, I was wondering what are the scientific problems behind the research? I must admit that the authors indeed conducted some work, but I failed to get the significance of this work.

> Thank you for your informative comment. To clarify the research gap, objective and contribution of this study, the introduction was revised as follows:

“A primary limitation of prior research examining resource use within the transport system lies in the restricted scope of system boundaries employed for re-source accounting. While direct material weight has been frequently utilized to assess resource use for transport infrastructure development, this approach presents chal-lenges in accurately estimating the practical environmental impact. Given that the ma-jority of resources are extracted through mining activities, and considering the docu-mented negative environmental [25] and biodiversity [26] impacts associated with these operations, the explicit consideration of mining activity volume is crucial for in-formed resource management discourse. The increasing extraction of natural resources via mining poses a substantial threat to the long-term sustainability of resources es-sential for the global energy transition [25]. Therefore, the volume of resource use, as viewed from the perspective of mining activity, should be adopted as a key indicator.

Limited scholarly attention has been directed towards analyzing resource utiliza-tion within the transportation sector from a mining perspective. While studies such as Takimoto et al., [28] and Watari et al., [25] have identified substantial increases in mining demand driven by the automotive industry, based on the mining intensity of various vehicle types [29], a gap remains in the literature. Even within the automotive sector, resource use associated with infrastructure development has received scant analysis. Furthermore, other crucial transportation modes, including railways, water-ways, and aviation, have been largely overlooked. This omission precludes a compre-hensive comparative analysis of different transportation modalities that considers both vehicle production and infrastructure requirements. Consequently, this study aims to develop a standardized classification framework for transport infrastructure, enabling comparisons across diverse transportation modes. Subsequently, by integrating trans-portation means with their associated infrastructure (roadways, railways, aviation, and waterways), the research will estimate the resource efficiency of the transportation system from a mining demand perspective. The contributions of this study are two-fold: (1) the provision of a standardized transport infrastructure framework for inter-modal comparison, applicable also to the analysis of other environmental indicators within the transport system; and (2) the identification of the most resource-efficient transportation mode, considering mining activity, through the integrated assessment of both vehicle and infrastructure.”

Round 2

Reviewer 1 Report

Comments and Suggestions for Authors

The authors have carried out a thorough and careful revision and the revised manuscript improved a lot in terms of technical quality and language. Therefore, I would recommend it for publication in the Journal.

Author Response

Thank you very much for reviewing the revised manuscript.

Reviewer 2 Report

Comments and Suggestions for Authors

Thank you for the revisions for my comments. However, I still feel the comments  has not completely dispelled my previous concerns. Since I do not entirely agree with the objective and methodology of this study, I remain open mind to the opinions of the author and other reviewers.

            Comments on the Quality of English Language

Although some sentences are revised, I still find the English expression and wording can be further improved. This paper will be beneficial to be proofread by a native English speaker. 

Author Response

[Comment]However, I still feel the comments  has not completely dispelled my previous concerns.

 

[Answer]Thank you for your comment.

It is imperative to clarify that the primary objective of this research is not the development of a novel methodological framework. Rather, this study focuses on the application of an established indicator, Total Material Requirement (TMR), to evaluate both vehicular and infrastructural components within a transportation system. This application is conducted under a standardized framework, which constitutes the core contribution of this investigation, as outlined in the Introduction.

While a substantial body of literature addresses environmental impacts such as greenhouse gas emissions, nitrogen oxides (NOx), and sulfur oxides (SOx), this research distinguishes itself by prioritizing resource utilization from a mining perspective. This approach is analogous to established academic studies that utilize such emissions as an evaluative metric within specific domains. Consequently, we posit that the present study maintains a comparable level of academic rigor and relevance.

Although the contributions and objectives of this research were articulated in the initial revision, a reviewer's comment highlighted the need for a more comprehensive elucidation regarding the selection of resource-related indicators from a mining-centric viewpoint within the Methodology section. To adequately address this concern and underscore the academic significance of this assessment, a supplementary paragraph has been incorporated into the Methodology section. This addition provides a detailed rationale for the utilization of TMR and elucidates its importance in the context of this study.

“Natural resources are extracted from the lithosphere and ultimately dispersed in-to the ecosphere. This process of natural resource utilization engenders environmental impacts [32], for which various methodological approaches within Life Cycle Impact Assessment (LCIA) have been documented [33]. This study focuses on the quantifica-tion of natural resource use volume. Natural resources, originating within the litho-sphere, are subject to extraction and exploitation through mining activities, which rep-resent the depletion of lithospheric natural capital stocks. Evaluating the scale of min-ing activities enables the quantification of natural resource extraction.

One potential approach to estimating mining activity scale involves measuring the associated land area, given that mining activities are categorized as a form of an-thropogenic land use [34]. Land use is a recognized factor influencing environmental impacts within LCIA frameworks. Common indicators of land use include land occu-pation and transformation areas [35]. Notably, the quantification of land surface area (m²) does not comprehensively reflect the total volume of extracted resources, includ-ing mine waste, as it fails to account for variables such as mine depth. Given the ab-sence of a universally accepted quantification approach for land use, the exclusive ap-plication of land surface area to evaluate mining activities and resource use may be deemed inadequate.

Therefore, in lieu of land surface area, a specific metric for quantifying resource use derived from mining activities is warranted. Weight provides an alternative meas-ure of the scale of land disturbance associated with mining. Indeed, mining activities globally displace over 57 billion tons of lithospheric material annually [36]. To evaluate the volume of natural resource use in the transportation system, this study focuses on the quantification of land disturbance weight resulting from the mining of primary lithospheric resources. This aligns with the principle of Total Material Requirement (TMR), which is an indicator to quantify resource use [37].”

Reviewer 3 Report

Comments and Suggestions for Authors

The revisions and responses are not as good as expected. For example, Fig. 5 in the revised manuscript is still blurry. Why not revising them as suggested in the last round of review? Is that difficult? Also, the core contributions are not clear enough.

Tha authors should be serious about the presented research. The authors are strongly recommended to thoroughly polish the whole manuscript from all aspects.

 

Author Response

The revisions and responses are not as good as expected. For example, Fig. 5 in the revised manuscript is still blurry. Why not revising them as suggested in the last round of review? Is that difficult?

>We used the original high quality version of this image even for the revised version. Why it looks blurry would be due to the size of image. As such, in this version, we picked up some to demonstrate the feature for the different transportation modes, so that it could be seen more clearly. Hope that this version meets your demand.

 

The authors should be serious about the presented research. The authors are strongly recommended to thoroughly polish the whole manuscript from all aspects.

>Thank you for your comment.

While we have made a conscientious effort to address the comments, if it appears that we have fallen short, we would be grateful if you could provide specific guidance on areas for improvement.

It is imperative to clarify that the primary objective of this research is not the development of a novel methodological framework. Rather, this study focuses on the application of an established indicator, Total Material Requirement (TMR), to evaluate both vehicular and infrastructural components within a transportation system. This application is conducted under a standardized framework, which constitutes the core contribution of this investigation, as outlined in the Introduction.

 

While a substantial body of literature addresses environmental impacts such as greenhouse gas emissions, nitrogen oxides (NOx), and sulfur oxides (SOx), this research distinguishes itself by prioritizing resource utilization from a mining perspective. This approach is analogous to established academic studies that utilize such emissions as an evaluative metric within specific domains. Consequently, we posit that the present study maintains a comparable level of academic rigor and relevance.

 

Although the contributions and objectives of this research were articulated in the initial revision, a reviewer's comment highlighted the need for a more comprehensive elucidation regarding the selection of resource-related indicators from a mining-centric viewpoint within the Methodology section. To adequately address this concern and underscore the academic significance of this assessment, a supplementary paragraph has been incorporated into the Methodology section. This addition provides a detailed rationale for the utilization of TMR and elucidates its importance in the context of this study.

 

“Natural resources are extracted from the lithosphere and ultimately dispersed in-to the ecosphere. This process of natural resource utilization engenders environmental impacts [32], for which various methodological approaches within Life Cycle Impact Assessment (LCIA) have been documented [33]. This study focuses on the quantifica-tion of natural resource use volume. Natural resources, originating within the litho-sphere, are subject to extraction and exploitation through mining activities, which rep-resent the depletion of lithospheric natural capital stocks. Evaluating the scale of min-ing activities enables the quantification of natural resource extraction.

One potential approach to estimating mining activity scale involves measuring the associated land area, given that mining activities are categorized as a form of an-thropogenic land use [34]. Land use is a recognized factor influencing environmental impacts within LCIA frameworks. Common indicators of land use include land occu-pation and transformation areas [35]. Notably, the quantification of land surface area (m²) does not comprehensively reflect the total volume of extracted resources, includ-ing mine waste, as it fails to account for variables such as mine depth. Given the ab-sence of a universally accepted quantification approach for land use, the exclusive ap-plication of land surface area to evaluate mining activities and resource use may be deemed inadequate.

Therefore, in lieu of land surface area, a specific metric for quantifying resource use derived from mining activities is warranted. Weight provides an alternative meas-ure of the scale of land disturbance associated with mining. Indeed, mining activities globally displace over 57 billion tons of lithospheric material annually [36]. To evaluate the volume of natural resource use in the transportation system, this study focuses on the quantification of land disturbance weight resulting from the mining of primary lithospheric resources. This aligns with the principle of Total Material Requirement (TMR), which is an indicator to quantify resource use [37].”

 

Round 3

Reviewer 2 Report

Comments and Suggestions for Authors

Thank you for revising this manuscript to address my comments.

I think a systemically rewritten manuscript is needed, not just the research gap, objective, and contribution sections.

Comments on the Quality of English Language

Although the revised parts are improved, I still find the English expression and wording can be further improved. This paper will be beneficial if it is proofread by a native English speaker. 

Reviewer 3 Report

Comments and Suggestions for Authors

After two rounds of revision, I reluctantly recommend accepting the paper for publication.