Tandem Design of Bus Priority Based on a Pre-Signal System

Round 1

Reviewer 1 Report

Dear authors,

Dear Editor,

Thank you very much for the opportunity to read your manuscript “Tandem Design of bus priority based on pre-signal system”. The studied subject is relevant in the actual road system management in order to get more efficient systems, giving a special priority to bus.

Despite the relevance of the subject, some aspects weaken the manuscript, namely:

1) theoretical discussion is scarce, either on the theme in general or on other models already applied, and it is not possible to identify the innovation of the proposed model nor its relevance for sustainability;

2) bibliographical references are extremely scarce, outdated and from a limited territorial area, excluding all studies carried out around the world. Since this is a hypothetical model, there are no constraints on opening the range of studies;

3) the discussion section presents results, essentially from the experimented model, with no real discussion of the results, but rather a description of them. The potentialities and limitations of the presented model should be discussed to.

In this sense, in order to amplify the scientific soundness of the manuscript, It is suggested the reinforcement of the manuscript, namely in the aspects presented above. Some small notes are also left following the manuscript structure.

KEYWORDS

• “Tandem design” is a keyword and is present in the title, however there is any clear reference in the text about the concept;
• The same with “public transport priority”. The authors could quickly explain the advantages of public transport priority in the transport system in the text (as it is in the abstract);

1. INTRODUCTION

• Lines 22 and 28 – “cities at home”. There is no previous spatial reference in order to the reader understand this reference;
• The theoretical basis is scarce, with the identification of a set of previous studies without any further debate;

2. MATERIALS AND METHODS

• Titles of figures 1 to 3 have a typo on “fingure”
• What is the difference between figures 2 and 3?

3. RESULTS

• Lines 109 to 212 – these assumptions should be in the previous section as these are not results;
• Line 135 – please, check if it broken line is ABDEG or ABCDEG
• Line 158 – check the reference to “Figure 2-1”
• Line 273 – please, check the reference to figure 6;

4. DISCUSSION

• This section is the continuation of the results section as this is the application of the previously presented models. In this section there is no clear discussion about the results Authors should consider to improve this section, according to the guidelines of the journal, perhaps combine the results and discussion sections: Discussion: Authors should discuss the results and how they can be interpreted in perspective of previous studies and of the working hypotheses. The findings and their implications should be discussed in the broadest context possible and limitations of the work highlighted. Future research directions may also be mentioned. This section may be combined with Results.

REFERENCES

The list of references is quite scarce, not properly updated (only one reference from 2020, and the previous one form 2016) and territorial constrained. The references do not correspond to the journal formatting.

Author Response

The authors gratefully acknowledge the constructive comments on our work provided by you. Please accept our thanks for your kindness and time in reviewing this article. Please check the revised version and our replies in the attached file.

Author Response File: Author Response.pdf

Reviewer 2 Report

In this paper, the authors analyze the efficiency of a tandem design based on the pre-signal system on intersections. In particular, the authors focusing their attention on the bus and social vehicle delay.

The topic is interesting, but contributions are not well clarified due to the lack in literature review. Moreover, the structure of the paper makes the treatment of this work unclear and difficult to understand. I have several strategic, technical, and organizational issues. For these reasons, I suggest a major revision.

 

Strategic issues

1. The contributions of this paper to the existing literature are not clearly highlighted. How do the authors advance the knowledge compared to the existing literature? What do the authors propose to differentiate their work from the current literature? I do not find the answer to these questions throughout the manuscript, or the answers are too simplified. Are the authors strictly rely on the existing literature or do they propose some novelties? The statement of contributions and the difference with current literature should be better emphasized for publication in this high-quality journal. For instance, a well-accepted method to compute the delay at the junction is that of the Highway Capacity Manual (2016). However, this method is never recalled in this paper.
2. This paper is not clearly motivated. There are a few discussions in the Introduction, but it is difficult for me to enucleate the motivations. Thus, a finer motivation is required to illustrate the importance of this work. Moreover, it is not clear how authors situate their work within the existing literature. For instance, bus priority is one of strategies needed to improve the reliability of transit, but the authors did not mention it. And this fact may help motivate the paper. I recommend to consider the following research papers, where reliability was defined, measured and managed as well as applied to real case studies. They can help motivate the paper since bus priority is a strategy to improve reliability. For instance,

• https://doi.org/10.1016/j.tre.2007.10.002
• https://doi.org/10.1016/j.tra.2009.07.006
• https://doi.org/10.1109/TITS.2016.2581024;
• https://doi.org/10.1109/TITS.2016.2585342
• https://doi.org/10.1109/MITS.2018.2889713

3. Conclusions are too poor and no consideration was made of the limitations of this study and its possible future developments. Moreover, some practical implications should be provided. In this way, a reader understands better two key aspects: the possible direction for further improvements and the relevance to this work towards practitioners.

 

Technical issues

4. Bus priority may be given by right-ot-way (spatial) priority and/or time (temporal) priority. These facts should be pointed out at the beginning.
5. The concept of tandem design is adopted but it is never presented. Explain what this concept mean.
6. Literature needs to be better investigated to clarify better the real contributions of this work. What are the results obtained in previous studies? How were they obtained? What kind of analyzes were conducted? Which methodologies have been applied?
7. In section 2, the authors mention 3 types of bus lanes without a specific description. Furthermore, no differences are noted between figures 2 (medium bus lanes) and 3 (secondary bus lane). To better evaluate the effectiveness of the pre-signal systems, the characteristics of each bus lines types need a more detailed description. In fact, different bus lines conformations can bring different results in terms of performance and safety as reported by the following papers:

• https://doi.org/10.1016/j.proeng.2016.01.288
• https://doi.org/10.1016/j.aap.2021.106258

8. What do the authors mean by "social vehicle"?
9. The intersections analyzed by the authors are not contextualized. Is it a real scenario? Where does this data come from? how were the results obtained? I think that they are important details to understand the actual applicability of the model.
10. Some polygons appear to be incorrectly defined (page 6, “polygonal OABCDJ” … “quadrilateral “BCDI”).
11. Figure 12: the difference between straight lines OW and AD is unclear.
12. Equations 23, 29 and 31 seems incomplete. Moreover, many equations are not clearly legible. Please review the formatting of the equations.

 

Organisational issue

13. The authors merged the literature review within the introduction. To better clarify what in this paper is new, I suggest providing a separate section of the literature review where the authors could discuss past research. Next, at the end of the section Literature Review, the authors should summarize the gaps with past research, because a reader can understand better how this paper differs from the other studies.

The structure of this paper is unclear and does not highlight the results. If the aim of this work is to assess the improvement by adopting a “tandem design”, the authors cannot illustrate their comparison about traffic delays at the end of the discussion chapter. In my opinion, table 2 should already be described in the result section and the discussion should be focused exclusively on this kind of result. Moreover, the “Material and Methods” section does not explain how the authors decided to do this kind of analysis. Maybe a flowchart scheme could help to better understand the analysis process. In addition, section results also contain theoretical content which is in the wrong section.

Author Response

Dear reviewer,

Thank you very much for your kindly comments on our manuscript. There is no doubt that these comments are valuable and very helpful for revising and improving our manuscript. In what follows, we would like to answer the questions you mentioned and give detailed account of the changes made to the original manuscript. Please see the attachment.

Author Response File: Author Response.pdf

Round 2

Reviewer 1 Report

Dear Authors,

Congratulations for your investment to improve the manuscript. This second version of the manuscript is indeed more organized and deepened. The objective are clearer now, as the innovation of the study compared to the literature.

I consider that the modifications in the paper and the answers point-to-point to all my questions correspond to my suggestions.

In this sense, I consider that the paper is now eligible for publication.

With my best regards.

Author Response

Dear reviewer,

Thank you very much for all your comments. Without your opinion, our manuscript would not have been improved so much. Thank you again and wish you every success in your work.

Reviewer 2 Report

Please see the attached file.

Comments for author File: Comments.pdf

Author Response

Dear reviewer, Thank you for all your suggestions. We are very sorry for the lack of improvement last time. We have made detailed changes according to your suggestion this time. Please see the attachment .

Author Response File: Author Response.pdf

Round 3

Reviewer 2 Report

After this round review this paper is improved and can be accepted.