Research on the Decoupling Relationship between Transportation Land and Population Growth: A Case of Guangdong Province in China

Round 1

Reviewer 1 Report

The study delves into the decoupling relationship between transportation land and population growth in Guangdong Province, a topic of significant practical significance and theoretical value. This research is crucial for understanding and addressing issues such as the imbalance between population and transportation infrastructure supply and demand and optimizing resource allocation in regional development in China. Identifying and analyzing the relationship between transportation land and population changes under the "centre-periphery" pattern in Guangdong Province provides a roadmap for future regional development planning and transportation investment strategies.

Prior to publication, several suggestions are offered to enhance the suitability of the article:

1. Introduction: While the introduction provides detailed background information, it lacks specific research questions. It is essential to outline the specific research objectives of the paper clearly.
2. The Literature Review part is missing, although some parts of the literature review are illustrated in the first introduction part. It still needs to be more comprehensive, including recent research trends, current limitations, and conceptual frameworks guiding the research. More citations are needed.
3. In part 3, a Measurement Framework should presented, outlining the data sources and analytical methods used.
4. While the paper utilizes hotspot analysis and decoupling models, exploring additional econometric or spatial econometric models in the methodological part, such as spatial panel data models, could enhance the accuracy and comprehensiveness of the decoupling analysis.
5. A more detailed description is needed while spatial heterogeneity is mentioned. Utilizing GIS technology or other spatial statistical methods (GWR?) for a more detailed spatial autocorrelation analysis could reveal specific differences in transportation land and population distribution among different regions.
6. The discussion section should address the research questions, contributing to a more coherent overall structure of the paper.
7. The paper proposes a series of measures based on the research findings. These measures, such as adopting different transportation construction and management strategies for different decoupling types of regions, are of paramount importance. However, the policy recommendations should further specify implementation plans for various decoupling states, considering a comprehensive range of economic, social, and environmental factors.

Author Response

1. The reviewer's comment:

Introduction: While the introduction provides detailed background information, it lacks specific research questions. It is essential to outline the specific research objectives of the paper clearly.

Our response:

We thank the reviewer for the kind consideration and constructive comments on our manuscript. As suggested by the reviewer, we have incorporated the specific questions into the manuscript and highlighted them in red.

2. The reviewer's comment:

The Literature Review part is missing, although some parts of the literature review are illustrated in the first introduction part. It still needs to be more comprehensive, including recent research trends, current limitations, and conceptual frameworks guiding the research. More citations are needed.

Our response:

We highly agree with your viewpoint. As suggested by the reviewer, we have briefly summarized the current research trends in the literature review section. After analyzing all relevant literature on the relationship between transportation land use and population, we still believe that research on the relationship between population and land use changes, as well as transportation land use, remains the most relevant. We have supplemented the relevant literature and have not focused on other types of research (such as land use change studies or studies on other specific land types) as they are less relevant to this paper. Additionally, we have outlined the limitations of current research. All specific modifications have been highlighted in red in the draft.

3. The reviewer's comment:

In part 3, a Measurement Framework should presented, outlining the data sources and analytical methods used.

Our response:

We sincerely thank the reviewer for careful reading. We have outlined the data sources and analysis methods on pages 4 and 5.

4. The reviewer's comment:

While the paper utilizes hotspot analysis and decoupling models, exploring additional econometric or spatial econometric models in the methodological part, such as spatial panel data models, could enhance the accuracy and comprehensiveness of the decoupling analysis.

Our response:

Thank you for your advice. During the experiment, we tried various spatial econometric methods to further explore or explain the results of decoupling analysis, but unfortunately, the results of these methods were not satisfactory.

5. The reviewer's comment:

A more detailed description is needed while spatial heterogeneity is mentioned. Utilizing GIS technology or other spatial statistical methods (GWR?) for a more detailed spatial autocorrelation analysis could reveal specific differences in transportation land and population distribution among different regions.

Our response:

Thank you for your suggestions. We have added Moran's I analysis of spatial autocorrelation. The specific content has been marked in red in the manuscript.

6. The reviewer's comment:

The discussion section should address the research questions, contributing to a more coherent overall structure of the paper.

Our response:

We thank the reviewer for the kind consideration and constructive comments on our manuscript. We will make appropriate adjustments to the conclusion based on your feedback

7. The reviewer's comment:

The paper proposes a series of measures based on the research findings. These measures, such as adopting different transportation construction and management strategies for different decoupling types of regions, are of paramount importance. However, the policy recommendations should further specify implementation plans for various decoupling states, considering a comprehensive range of economic, social, and environmental factors.

Our response:

We thank the reviewer for the kind consideration and constructive comments on our manuscript. As suggested by the reviewer,we have re-debated the conclusions and discussions, and the specific content has been marked in red in the manuscript.

Reviewer 2 Report

Dear authors,

The importance of not having too much land area covered by transport infrastructure is indeed an issue that deserves greater attention from the part of researchers. I find that the results reported through the submitted manuscript are interesting, but I also have some comments that I think could be useful for preparing a better version of the manuscript. Also, there are some issues that have to be clarified.

Title: to my opinion a shorter title would have a greater impact, and would be easier to be understood by readers. But this is up to the authors to decide the best version.

Abstract: 

• 

  I find it too long and hard to understand

• 

  Typos should be corrected

• 

  The authors state: “Using hotspot and decoupling models”. Is “hotspot” a method? I think the authors refer to either “exploratory spatial data analysis (ESDA)” or “spatial autocorrelation indexes” (Getis-Ord G*, Moran’s I etc.)

• 

  Affirmations that make no sense to me:

• 

  “percentage of transportation land in the proportion of transportation land in the peripheral areas of” 

• 

  “The decoupling results of PRD remained mainly weak decoupling and expanding negative decoupling from 2010 to 2020”

Introduction

• 

  I find that the introduction is well written and contextualizes well the research carried out by the authors

•  

Study area

• 

  An useful and nice section

• 

  “Humanistic history” (Line 155). What does it refer to?

• 

  “Best-developed”? I think we usually use “highly developed” or “highest developed”…

Methods

• 

  Table 1 - I find it highly useful and clarifying

• 

  Why using Getis-Ord G* instead of Moran’s I?

Results

• 

  Figure 4 (upper part) - unit of measurement not indicated at the legend

• 

  How has “land use data” been acquired? Was it computed by authors in GIS or taken from official statistics?

• 

  What do “rural roads” include? What does the category “highways” include? Where are national roads and county roads, i.e. in which of the two categories?

• 

  Figure 6 (bottom half): was it population (absolute values) or population density that has been employed to compute Getis-Ord G*?

• 

  “increase in land” - I suspect that the authors wanted to state “increase in transportation land” - paragraph 359 - 374. This confusion is present in more than one instance

• 

  I would suggest using the same concepts (and at the same time more precise concepts) for describing the same reality throughout the paper. Exemple: instead of man-land relationship (which are broad concepts) the authors could use “relationship between population growth  and transportation land”. It would be more accurate, especially throughout the Results section. 

• 

  Figure 8 - unit of measurement for values is missing

Discussions and Conclusion

• 

  “The study employs hot spot and decoupling models” - The models are not usually called “hot spot” (see a similar suggestion above, in the “Abstract” section)

• 

  The authors report very interesting results: “this study reveals that, with changes in population distribution patterns, the mismatch between transportation land and population scale in economically disadvantaged regions becomes increasingly severe, with a pronounced decoupling between transportation land and population.” However, the further statement, that “This prompts us to reconsider the issue of transportation waste” needs stronger arguments as the issue of transport corridors that link cities situated at far distances need to be differentiated from transport routes that are designed to serve local communities. This has not been done in the current research. Hence, the discussion section should acknowledge this fact. The paper would best integrate such an analysis that distinguishes between the two.

• 

  To my best of understanding, policy implications debated in lines 442-452 are not supported by evidence as long as the analysis is not disaggregated to differentiate between local roads and national expressways.

• 

  Limitations of the approach are not addressed.

• 

  Theoretical implications are not discussed.

• 

  Added values for the broader literature is not discussed.

Looking forward to reading a better version and to reading the published paper! For the moment I recommend major revisions as some conclusions (policy implications) are not supported by the methodological approach. The analysis could be enriched (by differentiating between transport infrastructures that serve local communities and large corridors that serve cities of national importance) or at least acknowledge the limitations. But acknowledging limitations would lead to retraction of many policy implications statements... and hence considerably decreasing the relevance of the results.

Kind regards,

The reviewer

This is up to proofreaders to comment on it.

Author Response

1. The reviewer's comment:

Title: to my opinion, a shorter title would have a greater impact, and would be easier to be understood by readers. But this is up to the authors to decide the best version.

Our response:

We thank the reviewer for the kind consideration and constructive comments on our manuscript. As suggested by the reviewer, we have changed the title to "Research on the Decoupling Relationship between Transportation Land and Population Growth: A Case of Guangdong Province in China"

2. The reviewer's comment:

Abstract: I find it too long and hard to understand

Our response:

We thank the reviewer for the kind consideration and constructive comments on our manuscript. As suggested by the reviewer, We have made necessary simplifications to the abstract.

3. The reviewer's comment:

Abstract: Typos should be corrected

Our response:

We were really sorry for our careless mistakes. Thank you for your reminder. And here we did not list the changes but marked them in red in the revised paper.

4. The reviewer's comment:

Abstract: The authors state: “Using hotspot and decoupling models”. Is “hotspot” a method? I think the authors refer to either “exploratory spatial data analysis (ESDA)” or “spatial autocorrelation indexes” (Getis-Ord G*, Moran’s I, etc.)

Our response:

We thank the reviewer for the kind consideration and constructive comments on our manuscript. As suggested by the reviewer, we have corrected the “hotspot " into the “Exploratory Spatial Data Analysis (ESDA) "

5. The reviewer's comment:

Abstract: Affirmations that make no sense to me:

“percentage of transportation land in the proportion of transportation land in the peripheral areas of” 

“The decoupling results of PRD remained mainly weak decoupling and expanding negative decoupling from 2010 to 2020”

Our response:

We sincerely thank the reviewer for careful reading. As suggested by the reviewer, we have made corrections to the relevant sentences (see page 1).

6. The reviewer's comment:

Introduction： I find that the introduction is well written and contextualizes well the research carried out by the authors

Our response:

We appreciate your summary of the manuscript and encouraging comments.

7. The reviewer's comment:

Study area: A useful and nice section

Our response:

We appreciate your summary of the manuscript and encouraging comments.

8. The reviewer's comment:

Study area: “Humanistic history” (Line 155). What does it refer to?

Our response:

We sincerely thank the reviewer for careful reading. It may be better translated as humanities and history here. Humanities and history refer to the content of human social activities, regional culture, etc., including but not limited to social phenomena, historical events, and characters in different historical periods. In the process of rapid economic development in Guangdong, there are many elements of regional culture, events, etc., which are also important factors affecting the uneven development of the region.  For example, the influence of Chaoshan cultural soft power on economic development, and the problem of corruption among local officials[1,2].

9. The reviewer's comment:

Study area: “Best-developed”? I think we usually use “highly developed” or “highest developed”…

Our response:

We thank the reviewer for the kind consideration and constructive comments on our manuscript. What we want to express here is "the best development environment".  As suggested by the reviewer, replacing it with "highly developed" or "highest developed" may duplicate the meaning of the second half of the sentence, so we have corrected it to "the best development environment"(see page 4).

10. The reviewer's comment:

Methods： Table 1 - I find it highly useful and clarifying

Our response:

We appreciate your summary of the manuscript and encouraging comments.

11. The reviewer's comment:

Methods： Why using Getis-Ord G* instead of Moran’s I?

Our response:

We sincerely thank the reviewer for careful reading. We think that using Getis-Ord G* is a better and intuitive way to show the spatial mismatch between population and per capita land use.

12. The reviewer's comment:

Results: Figure 4 (upper part) - unit of measurement not indicated at the legend

Our response:

We sincerely thank the reviewer for careful reading. As suggested by the reviewer, We have added the measurement unit in the legend(see Figure 4)

13. The reviewer's comment:

Results:How has “land use data” been acquired? Was it computed by authors in GIS or taken from official statistics?

Our response:

The land data used in the study is derived from land resource surveys published by the Guangdong Provincial Department of Natural Resources. We have explained its origin on page 4.

14. The reviewer's comment:

Results: What do “rural roads” include? What does the category “highways” include? Where are national roads and county roads, i.e. in which of the two categories?

Our response:

We sincerely thank the reviewer for careful reading. According to the definition of rural roads by the Ministry of Transport of the People's Republic of China in 2018, it generally refers to roads that connect towns and administrative villages, including three levels: county roads, township roads, and village roads.

According to the "Mark rules of highway route and number of national trunk highway " of the People's Republic of China, highways are multi-lane roads designed for separate directions and lane driving, with full access control. National roads include national highways and ordinary national roads, and provincial roads include provincial highways and ordinary provincial roads. County roads belong to rural roads.

15. The reviewer's comment:

Results: Figure 6 (bottom half): was it population (absolute values) or population density that has been employed to compute Getis-Ord G*?

Our response:

We sincerely thank the reviewer for careful reading. We use the total population to calculate Getis-Ord G*.

16. The reviewer's comment:

Results: “increase in land” - I suspect that the authors wanted to state “increase in transportation land” - paragraph 359 - 374. This confusion is present in more than one instance

Our response:

We sincerely thank the reviewer for careful reading. As suggested by the reviewer, We have corrected “increase in land” into “increase in transportation land”(see page 11)

17. The reviewer's comment:

Results: I would suggest using the same concepts (and at the same time more precise concepts) for describing the same reality throughout the paper. Exemple: instead of man-land relationship (which are broad concepts) the authors could use “relationship between population growth  and transportation land”. It would be more accurate, especially throughout the Results section. 

Our response:

We sincerely thank the reviewer for careful reading. Based on your suggestions, we have replaced the entire man-land relationship and marked it in red in the draft.

18. The reviewer's comment:

Results: Figure 8 - unit of measurement for values is missing

Our response:

We sincerely thank the reviewer for careful reading. As suggested by the reviewer, We have added the measurement unit in the legend(see Figure 8)

19. The reviewer's comment:

Discussions and Conclusion：“The study employs hot spot and decoupling models” - The models are not usually called “hot spot” (see a similar suggestion above, in the “Abstract” section)

Our response:

We sincerely thank the reviewer for careful reading. As suggested by the reviewer, we have corrected the “hotspot " into the “exploratory spatial data analysis (ESDA) "(see page 12)

20. The reviewer's comment:

Discussions and Conclusion:The authors report very interesting results: “this study reveals that, with changes in population distribution patterns, the mismatch between transportation land and population scale in economically disadvantaged regions becomes increasingly severe, with a pronounced decoupling between transportation land and population.” However, the further statement, that “This prompts us to reconsider the issue of transportation waste” needs stronger arguments as the issue of transport corridors that link cities situated at far distances need to be differentiated from transport routes that are designed to serve local communities. This has not been done in the current research. Hence, the discussion section should acknowledge this fact. The paper would best integrate such an analysis that distinguishes between the two.

Our response:

We thank the reviewer for the kind consideration and constructive comments on our manuscript. As suggested by the reviewer, we have revised the discussion section to provide a more detailed discussion of the transportation land situation in peripheral areas, and modified the original generalisation of land waste. However, we acknowledge that the data we currently have cannot distinguish between transportation corridors connecting distant cities and transportation routes aimed at serving local communities.

21. The reviewer's comment:

Discussions and Conclusion: To my best of understanding, policy implications debated in lines 442-452 are not supported by evidence as long as the analysis is not disaggregated to differentiate between local roads and national expressways.

Our response:

We thank the reviewer for the kind consideration and constructive comments on our manuscript. We have revised the discussion section and re-debated the policy implications.  The specific content has been marked in red in the manuscript.

22. The reviewer's comment:

Discussions and Conclusion: Limitations of the approach are not addressed..

Our response:

We thank the reviewer for the kind consideration and constructive comments on our manuscript. We will explain the limitations of the article in the discussion and conclusion section.

23. The reviewer's comment:

Discussions and Conclusion: Theoretical implications are not discussed.

Our response:

We thank the reviewer for the kind consideration and constructive comments on our manuscript. We will further explain the theoretical implications in the discussion and conclusion sections.

24. The reviewer's comment:

Discussions and Conclusion: Added values for the broader literature is not discussed.

Our response:

We thank the reviewer for the kind consideration and constructive comments on our manuscript. We will discuss the added value for the broader literature in the discussion and conclusion sections.

25. The reviewer's comment:

Looking forward to reading a better version and to reading the published paper! For the moment I recommend major revisions as some conclusions (policy implications) are not supported by the methodological approach. The analysis could be enriched (by differentiating between transport infrastructures that serve local communities and large corridors that serve cities of national importance) or at least acknowledge the limitations. But acknowledging limitations would lead to retraction of many policy implications statements... and hence considerably decreasing the relevance of the results.

Our response:

We greatly appreciate the reviewer's comments and will carefully consider your suggestions and incorporate relevant changes into the manuscript.

Round 2

Reviewer 1 Report

The improvement in the expository aspects as well as in the argumentation and order of the methodology, is substantial. The article now clearly states its objectives and demonstrates that it is an exercise of interest.