Quantifying the Environmental Impact of Vehicle Emissions Due to Traffic Diversion Plans for Road Infrastructure Construction Projects: A Case Study in China

Round 1

Reviewer 1 Report

Totally I think you should explain more about the numbers and expand your scientific discussions. The paper mostly includes numbers and their explanations and scientific reasons are not enough.

 

Figure 2: I do not understand the difference between plan A, C and D.

Table 4: Authors should explain why CO2 in vehicle emissions is so much higher than other air pollutants.

Table 5: How did you reach these environmental impacts?v

Comments for author File: Comments.pdf

Author Response

Dear reviewer,

Firstly, we really appreciate your comments on our work, and they are very helpful indeed. Please find below a summary explaining how we have responded to each of the comments.

(1) comment 1: Totally I think you should explain more about the numbers and expand your scientific discussions. The paper mostly includes numbers and their explanations and scientific reasons are not enough.

Response: Thank you for this constructive comment! We have further clarified our research aim and current research gap in the Introduction section (Line 72-76 and 106-108).

(2) comment 2: I do not understand the difference between plan A, C and D.

Response: Thank you for this constructive comment! We apologise for not clearly demonstrating the differences. It has been revised in Section 2.4 (Line 215-224).

(3) comment 3: Table 4: Authors should explain why CO2 in vehicle emissions is so much higher than other air pollutants.

Response: Thank you for this constructive comment! The reason for CO2 being much higher is discussed in Section 4.1 (Line 347-352).

(4) comment 4: Table 5: How did you reach these environmental impacts?

Response: Thank you for this constructive comment! The revision can be found in Section 3.1 (Line 255-257).

Reviewer 2 Report

 

The manuscript entitled Quantifying the Environmental Impact of Vehicle Emissions of Traffic Diversion Plans for Road Infrastructure Maintenance: a case study in China, presents a quantification the environmental impact of increased pollution emissions of traffic diversions due to traffic congestion for urban road-infrastructure maintenance projects based on the ReCiPe 2016 method.

 

The study proposed 10 types of traffic emissions by estimating emission factors and traffic conditions.  

Ø  The obtained results are suggestive represented by tables and figures.

Ø  According to the results, the different diversion plans could lead to different final environmental impacts.

Ø   Title is informative and reflects the contents and the Introduction chapter reflects a good documentation for the sensitivity analysis to explore the COPERT model performance and identify the main parameters that affect the model output variation.

Ø  The conclusions pointing out the relevance of results obtained and highlighted that the traffic speeds of traffic diversions before and during the road-infrastructure maintenance process are the major factors influencing the overall environmental impact. In addition, the consideration of others parameters as such as vehicle types, traffic behaviours, traffic speed and traffic flow are recommended to be considered in future studies.

Ø    The list of 66 references is consistent with good documentation in the field.

Author Response

Dear reviewer,

Firstly, we really appreciate your comments on our work, and they are very helpful indeed. The manuscript has been revised accordingly.

 

Reviewer 3 Report

The authors efforts are clear in the manuscript.  The presentation and outline of the manuscript are poor. The novelty of the research is not well presented. The paper has a contribution but not clearly presented in the introduction. The selection of roads/case study is not justified and well described.   Abstract needs more efforts. There are redundancy and ambiguous sentences in all manuscript. 

Flowchart in figure 1 is not well explained in the text. 

How did you get the numbers in table 3?

Titles of fig 2 are not clear 

..

..

..

Author Response

Dear reviewer,

Firstly, we really appreciate your comments on our work, and they are very helpful indeed. Please find below a summary explaining how we have responded to each of the comments.

(1) comment 1: The presentation and outline of the manuscript are poor.

Response: Thank you for this comment! The outline of this manuscript has been clarified in the Introduction section. (Line 109-115)

(2) comment 2:  The novelty of the research is not well presented. The paper has a contribution but not clearly presented in the introduction.

Response: Thank you for this comment! The significance and the novelty have been emphasized in the Introduction section. The main revisions can be found in Line 72-76 and Line 106-108.

(3) comment 3:  The selection of roads/case study is not justified and well described.

Response: Thank you for this comment! The reason for road selection is clarified (Line 207-209) and the case study has been further described (Line 216-225).

(4) comment 4:  Abstract needs more efforts.

Response: Thank you for this comment! The abstract has been revised.

(5) comment 5:  There are redundancy and ambiguous sentences in all manuscript.

Response: Thank you for this comment! The manuscript has been checked and revised.

(6) comment 6:  Flowchart in figure 1 is not well explained in the text.

Response: Thank you for this comment! The framework shown in Figure 1 has been explained (Line 131-136)

(7) comment 7:  How did you get the numbers in table 3?

Response: Thank you for this comment! The data source in Table 3 has been explained (Line 229)

(8) comment 7:  Titles of fig 2 are not clear

Response: Thank you for this comment! The title of Figure 2 has been revised.

Reviewer 4 Report

An interesting work on assessing the environmental impact of traffic diversion during road maintenance and repair works.

Overall comments: The element of the duration of works should be enhanced in your discussion. You should also further elaborate (especially in the discussion of results or conclusions) how your approach is integrated to a LCA of a project, since you focus on LCA in the introduction.  

Specific comments:

a. Please consider introducing the term "maintenance works" or similar into your keywords, as it is an integral part of your approach.

b. The methodology ( Section 2.2) should be further explained, i.e. the process that related input and output and the links between midpoints and endpoints should be elaborated. Please also explain the reasons for the selection of midpoints and endpoints in the methodology.

c. Please explain (Table 1 and text) what the road saturation index stands for. Is it v/c (i.e. flow/capacity)?

d. On line 211 you mention two assumptions. But you refer to 3 assumptions in the text below.

e. I agree with the limitation stemming from the "travel behaviour" aspect. You mention but, I believe, not clearly enough, that real-life data (e.g. FCD) can be used to incorporate the effect that traffic diversions have of travel choice, routing and driving profiles. I suggest you strengthen this point in your reference to the future outlook.

f. Your conclusions are restricted to those deriving directly from the case study. There is lack of general conclusions on how the research results may apply in other cases or how your methodology can advance research and/or policy making. I would suggest to consider to revise the part of limitations and future outlook and the part of conclusions in order to explore: i. The immediate conclusions of your methodology regarding the specific case; ii. The overall conclusions of your results regarding the scope of the research and beyond the specific case; iii. The overall applicability and contribution of your approach to science and policy; iv. Its limitations and, finally; v. Its future potential.

Author Response

Dear reviewer,

Firstly, we really appreciate your comments on our work, and they are very helpful indeed. Please find below a summary explaining how we have responded to each of the comments.

(1) comment 1: The element of the duration of works should be enhanced in your discussion.

Response: Thank you for this comment! The impact of the duration of work is clarified in Line 374.

(2) comment 2: how your approach is integrated to a LCA of a project

Response: Thank you for this comment! The importance of considering the traffic diversion element in LCA analysis has been clarified in Line 358-368.

(3) comment 3: Please consider introducing the term "maintenance works" or similar into your keywords, as it is an integral part of your approach.

Response: Thank you for pointing this out! After careful consideration, we believe the proposed quantification method can be used not only in the maintenance phase but also in all construction processes causing road closures. In this case, we change the term “maintenance” to “construction” and focused on assessing traffic diversion plans.

(4) comment 4: The methodology (Section 2.2) should be further explained, i.e. the process that related input and output and the links between midpoints and endpoints should be elaborated. Please also explain the reasons for the selection of midpoints and endpoints in the methodology.

Response: Thank you for this comment! The framework shown in Figure 1 has been explained (Line 132-136)

(5) comment 5: Please explain (Table 1 and text) what the road saturation index stands for. Is it v/c (i.e. flow/capacity)?

Response: Thank you for this comment! Please find the revision in Line 194.

(6) comment 6: On line 211 you mention two assumptions. But you refer to 3 assumptions in the text below.

Response: Thank you for pointing this out! It has been revised to be “three assumptions” (Line 235).

(7) comment 7: I agree with the limitation stemming from the "travel behaviour" aspect. You mention but, I believe, not clearly enough, that real-life data (e.g. FCD) can be used to incorporate the effect that traffic diversions have of travel choice, routing and driving profiles. I suggest you strengthen this point in your reference to the future outlook.

Response: Thank you for pointing this out! Using floating car data to reveal traveller behaviour has been highlighted in the future outlook section (Line 448).

(8) comment 8: Your conclusions are restricted to those deriving directly from the case study. There is lack of general conclusions on how the research results may apply in other cases or how your methodology can advance research and/or policy making. I would suggest to consider to revise the part of limitations and future outlook and the part of conclusions in order to explore: i. The immediate conclusions of your methodology regarding the specific case; ii. The overall conclusions of your results regarding the scope of the research and beyond the specific case; iii. The overall applicability and contribution of your approach to science and policy; iv. Its limitations and, finally; v. Its future potential.

Response: Thank you for this comment! It is really helpful! The conclusion has been revised to cover the overall conclusion and specific cases.

Round 2

Reviewer 3 Report

I accept the revised manuscript.