Slope Optimization (or “Sloop”): Customized Optimization for Road Longitudinal Profile Eco-Design
Round 1
Reviewer 1 Report
I read the reviewed article with interest. Its topic is very current and the proposed system of optimization of the longitudinal profile is very useful in planning the height arrangement of the road. The authors did a good job. As a recommendation for the continuation of research in the future, I recommend to include other construction types, not only cuts and embankments, but also structures such as bridges, tunnels, etc.
Author Response
We are grateful to your comments and suggestions that deeply improved the quality of our paper for a possible publication in Energies. All major changes in the manuscript are highlighted in blue. The revisions made are as follows.
Reviewer comment
I read the reviewed article with interest. Its topic is very current and the proposed system of optimization of the longitudinal profile is very useful in planning the height arrangement of the road. The authors did a good job. As a recommendation for the continuation of research in the future, I recommend to include other construction types, not only cuts and embankments, but also structures such as bridges, tunnels, etc.
Authors'reply
Thank you for this remark. Our case study does not include civil engineering structures such as bridges or tunnels. Our methodology is based on Project Energy Assessment Method (PEAM) and PEAM also models civil engineering structures as mentioned in (Bosquet et al, 2014), so there are no theoretical limits to include civil engineering structures in our methodology. However, Implementation can be complicated because the construction cost function may not be continuous. We plan to implement them according to users' requests.
This answer to your remark has been included in the section Discussion (last paragraph written in blue in the paper)
Finally, the revised manuscript has been entirely proof-read. We hope that our answer, along with the changes in our revised manuscript, will suit you.
With best wishes.
Reviewer 2 Report
In this paper the authors developed a method to optimize the transport infrastructure design considering both the longitudinal road profile and the environmental effect.
The model is based on the concept of "Sloop". Model formulation is correct, and the solution algorithm is reasonable. Again, the proposed model was applied to a case to validate its solution quality, and the presentation of numerical results are persuasive.
It is an article worth to be published in the journal Energies.
Author Response
Dear Reviewer,
We are grateful to your comments and suggestions that deeply improved the quality of our paper for a possible publication in Energies. All major changes in the manuscript are highlighted in blue.
Reviewer comment
In this paper the authors developed a method to optimize the transport infrastructure design considering both the longitudinal road profile and the environmental effect.
The model is based on the concept of "Sloop". Model formulation is correct, and the solution algorithm is reasonable. Again, the proposed model was applied to a case to validate its solution quality, and the presentation of numerical results are persuasive.
It is an article worth to be published in the journal Energies.
Authors reply
thank you for your positive comment.
Finally, the revised manuscript has been entirely proof-read.
With best wishes.
Reviewer 3 Report
The authors present a study that aims at optimizing the slope of a road to minimize the GWP emissions, by balancing construction phase and operation phase (i.e. the emissions of the vehicles). While the subject is of interest, I believe that the paper is too similar to the reference already published in [8], as stated by the authors. I do not believe that the additional contribution of this paper justifies its publication on an international journal.
In addition, there are further issues:
It is not clear why traffic data have been considered over 10 years, since the authors state that the lifetime of a road can be estimated over 25-30 years.
Diesel and gasoline cars are fine for the past, but electric vehicles need to be modeled as well to consider the future use of roads, since the authors consider a 25-years horizon. This is particularly true for the fact that EVs have regenerative braking, which could change significantly many of the assumptions of the model.
As in any model, it is important to perform a validation, or at least a sensitivity analysis on the main parameters that have been used. Without such analysis, how can the results be seen as reliable? Some parameters seem overly precise (e.g. Table 1), without a proper estimation of their potential variation the result is useless.
Also, the hypothesis of the constant traffic flows over 10 years seems quite simplistic. Again, an analysis of the variation of the optimized slope based on different traffic flow evolutions in the future may have provided most interesting insights.
Finally, the English quality is quite poor, there are many typos throughout the manuscript, which may often be removed by using word proofing tools.
Author Response
Dear reviewer,
We are grateful to your comments and suggestions that deeply improved the quality of our paper for a possible publication in Energies. All major changes in the manuscript are highlighted in blue. The revisions made are as follows:
1 ) Reviewer comment
The authors present a study that aims at optimizing the slope of a road to minimize the GWP emissions, by balancing construction phase and operation phase (i.e. the emissions of the vehicles). While the subject is of interest, I believe that the paper is too similar to the reference already published in [8], as stated by the authors. I do not believe that the additional contribution of this paper justifies its publication on an international journal.
Authors reply
The first paper was a proof of concept using a black box algorithm. We developed during two years a dedicated optimization algorithm completely described in this new paper. This algorithm paves the way for the diffusion of this methodology in the professional world.
Unfortunately, your remarks show that we have not been able to show this qualitative leap in this paper.
This is why we have substantially changed the article taking into account your remarks. This new version contains compared to the first version a sensitivity analysis of
the evaluation model with respect to the parameters of the longitudinal profiles; the optimization with respect to the construction parameters and traffic assumptions;
It is important to us to inform the community that we have moved from a proof of concept which was the subject of the first paper to a powerful software tool that allows us to conduct different sensitivity studies which substantially enrich the results provided by the method.
2) Reviewer comment
It is not clear why traffic data have been considered over 10 years, since the authors state that the lifetime of a road can be estimated over 25-30 years
Authors reply
You are right, it is a typo. Traffic over 25 years is considered. \\[1cm]
3) Reviewer comment
Diesel and gasoline cars are fine for the past, but electric vehicles need to be modeled as well to consider the future use of roads, since the authors consider a 25-years horizon. This is particularly true for the fact that EVs have regenerative braking, which could change significantly many of the assumptions of the model.
Authors reply
You are right, this evolution must be taken into account. The first version of our paper did not present it because the paper focuses on the optimization algorithms. Your remark show that this strategy is too restrictive and does not demonstrate the interest of this new algorithm to test different traffic assumptions.
We have added two fleet evolution scenarios which take into account the arrival of electric vehicles . The description and the analysis of these scenarios and their influence on the optimized profile have been added in the section results (written in blue in the new version). Globally, the profiles optimized according to the different scenarios are not identical but are close to one another for the road project studied.
4) Reviewer comment
As in any model, it is important to perform a validation, or at least a sensitivity analysis on the main parameters that have been used. Without such analysis, how can the results be seen as reliable?
Some parameters seem overly precise (e.g. Table 1), without a proper estimation of their potential variation the result is useless.
Authors reply
You are right, these numbers can evolve and a sensitivity analysis is quite relevant to detect the importance of them in the optimization. We do not mention it in the first version of this paper for a matter of readability of the paper which is still long. Your remark shows that we were wrong.
A sensitivity analysis of the parameters displayed on the Table 1 has been carried out and discussed for this new version (see the new subsection Sensitivity Analysis written in blue). 3 parameters have not significant influences (relative difference < 0.06 \%). One parameter has a small influence (relative difference = 0.35 %). This parameter models the lime treatment which is known by practitioners to engender GhG emissions. Our new algorithm facilitates this analysis. Thank you for your remark which enriches significantly our paper.
5) Reviewer comment
Also, the hypothesis of the constant traffic flows over 10 years seems quite simplistic. Again, an analysis of the variation of the optimized slope based on different traffic flow evolutions in the future may have provided most interesting insights.
Authors reply
Thank you for this remark which guided our work to enrich this paper. We hope that the change made described in the answers of the previous remarks answers to your expectations.
6) Reviewer comment
Finally, the English quality is quite poor, there are many typos throughout the manuscript, which may often be removed by using word proofing tools.
Authors Reply
The manuscript has been completely rewritten with a special attention on this point.
Finally, the revised manuscript has been entirely proof-read. We hope that our answers, along with the changes in our revised manuscript, will suit you.
With best wishes.
Round 2
Reviewer 3 Report
I appreciate the dedication of the authors in addressing the concerns that I have raised in the previous review process.
I think that the quality of the manuscript has improved. Thus, I recommend the acceptance of this research work to be published in Energies.
