Design and Simulation of a Variable Speed Limit System for Freeway Bottleneck Areas
Round 1
Reviewer 1 Report (Previous Reviewer 1)
The authors have addressed all the comments. Now the article is applicable for publication.
Author Response
Thank you! We will continue to work on related content in the future.
Reviewer 2 Report (Previous Reviewer 4)
The reviewer still has one more suggestion: the evaluation of a variable speed limit system with the use of crashes or safety surrogate measures such as conflicts should be mentioned as a future direction. Some latest relevant references are recommended as follows.
1. A multivariate method for evaluating safety from conflict extremes in real time
2. Study of automated shuttle interactions in city traffic using surrogate measures of safety
Author Response
Thanks for pointing this out. The point you suggested is very important for our future research. We have added the following to the paper to illustrate this point:
pp.16, lines 477 – 478
[Fourth, the VSL system can be evaluated using crashes or surrogate measures such as conflicts.]
Reviewer 3 Report (Previous Reviewer 5)
Thanks for the modification. But the manuscript is not ready for being accepted.
1.The response for the necessary of setting variable speed limits: There are no statistical tests performed by the authors to support any argument that there is a significant difference or not. Is there any proof that drivers would decelerate in advance following the speed limit warnings? The example should present the results under more different speed limits rather than only three. Giving a statement in conclusion cannot help to validate the contribution of this work.
2.“Drivers will adjust their speed immediately to prevent rear-end collisions when they 217 find congestion events without knowing it.” Without knowing what?
3.The response for VSL algorithm: “We replace the word “algorithm” with “rule” in the paper”. The change has not made thoroughly.
4.As the drivers may not follow the rules, it is not reasonable to set the driver's compliance as 100%. More sensitivity tests are needed.
5.Three different random seed simulation experiments for a scenario are not sufficient to get a conclusion. More experiments are needed.
Author Response
Please see the attachment.
Author Response File: 
Author Response.pdf
Reviewer 4 Report (New Reviewer)
Manuscript ID: sustainability-2032388
Design and Simulation of a Variable Speed Limit System for 2 Efficiency Improvement of Freeway Bottleneck Areas
Suggestions are Corrections for Authors:
Title and Abstract:
1. The title matches many related studies. It should be unique and simple that could verify the scope of the study. Revise it.
2. An abstract is found underrated. It is an important segment of an article that could portray positive or negative impacts on the readers. It is advised to rewrite the Abstract.
3. Abstract lacks its vital organs like the Authors directly jumped into findings earlier. See Lines 13-14. “The variable speed limit rules under different congestion conditions and adverse weather conditions are designed, and its parameters for a freeway are concretized”.
4. In the presence of available literature, what your study brings to readers or reviewers? Highlight in the Abstract together with the Novelty of the research.
5. Show Facts and Figures and then comment on important findings.
6. Verify the relationship of your study with the scope of the Journal. It is missing. How your study is related to Sustainable Development or Sustainability? Read the scope of the Journal and correct the manuscript. A separate subheading can also be inserted. But authors should highlight the relations in the Abstract, Review, and Conclusion Sections.
7. Revisit keywords.
Introduction:
1. Line 28-30. How do authors come to this conclusion without citing suitable literature? As a reviewer, I have found such corrections often in the manuscripts. Authors claim certain things and write biased statements. No citation rules are followed. In this manuscript, the same corrections are found. Definitions, facts and figures, and claims; all need support from the literature. Authors are advised to correct their manuscripts and follow the rules of literature citation. This is a serious and major correction. Comply.
2. Authors should reduce the introduction section and insert a review section. It is mandatory to include a review section, as a methodology can be drawn accordingly from the reviewed literature.
3. L 129-132. Complex sentences. The authors talked about the review, however, the review section is missing. Correction is required.
4. The research Gap is not defined properly.
5. No figure or table is found in the whole section which makes the whole section boring and dull. Authors are advised to put a literature table and figures to make the review section more vibrant.
Methodology and Models:
1. L 150-151. Definitions should be given in Introduction & Review sections. Correct it.
2. L 152-155. Very long and complex sentence. Authors are advised to proofread the manuscript. Use simple language so reviewers can easily understand the manuscript.
3. Figure 1 is not giving proper citations or sources. How authors developed this figure?
4. L 160-162. Complex sentence.
5. L 163-167. I wonder why the authors again put these lines at this stage of the manuscript. Totally misfit. Authors should review and read their manuscripts well.
6. L 172-174. Complex sentence. Authors are advised to review any good MDPI-published articles to explain their perspectives in the manuscript.
7. Figure 2. Again no citation. How did authors draw without a source? Justification or clarification is needed. These things are previously discussed in the literature. Authors should see and review all Figures.
8. I don’t see the link of Methodology with the study aim and objectives. Establish a link. The review & Methodology sections should be linked to the aim and study objectives. Correct it.
9. Table 1. Where these standards came from? No source or citation is given. This Table should literally be mentioned in the Review Section. Authors should correct and rectify all such loopholes.
10. Rules 1, 2, 3. Example: These must be taken from the literature. If not, how authors developed these rules? How these are related to the study aim and objectives. In my opinion, these sorts of things should have linked to Review. But in the review section, nothing is found to support this rule. Correction is required.
11. Section 3.1. No citations are observed. Steps are written, but it is not clear how authors write these steps. If these are taken from manuals, then again it is not mentioned. No related literature is observed. At this stage, these all are biased. Corrections are needed. Again I would say to link problems, review, methods, and findings sections.
12. Figures 4, 5, 7. Looks like the authors developed rules and scenarios on their own. No link is found in the previous literature.
13. It is suggested that the authors should rewrite the methodology again. Extract methods from the reviewed literature. Even steps and simulation processes. In the end, authors should link all processed and methods of research aims and objectives. Authors are also advised to put sustainability scope within this section as well.
14. Summarized the entire section as the last paragraph. Then come to the conclusion section. Correction is required.
Simulation Results and Discussion:
1. As per comments in the Methodology section, it is advised to link findings with objectives and sustainable development.
2. Show and discuss key findings and novel results.
3. At present, this section is not up to the mark. Show more results and make it an interesting section.
4. Conclude the whole result section concerning study objectives, research limitations, and scope.
Research Contribution and Novelty
1. This new section should be added to show the potential impact of the research.
2. Some policy implications can also be discussed in this section.
Conclusions:
1. Highlight objectives and key findings.
2. State how your study is different from the others.
3. Show major facts and figures.
4. Why reviewers should read this manuscript? Answer it.
5. Research Contribution in terms of sustainable development. Include it.
Concluding Remarks:
1. The manuscript needs major revisions.
2. Proofreading is massively required.
3. The flow between headings, subheadings, and paragraphs is missing.
4. Authors are advised to place suitable sentences in the right place with proper citations.
5. Authors should review literature citation rules and regulations. The manuscript lacks citation regulations.
6. Read and review any published SUSTAINABILITY ARTICLES to correct such major flaws.
7. Authors are advised to take advantage of the MDPI author services to proofread the manuscript.
Author Response
Please see the attachment.
Author Response File: Author Response.pdf
Round 2
Reviewer 3 Report (Previous Reviewer 5)
For the previous comments:
Authors did not reply to all of the concerns mentioned in the last review. For example, the question about different random seed simulation experiments. Does the simulation take a very long time? Why not test more and then get a more solidate conclusion? As the concerns cannot be solved in this manuscript and only can be solved in the future, this work should wait for the further work before it can be published.
For the updated version:
1. What is the meaning of the title of Section 2.3?
2. The forms of variables in Section 3 are confused. For example, drain12 is used in the formula, but drain12 is used in the text. Please keep them in consistence to avoid the confusion.
3. “Rules 1-3 can be used alone or in combination”. How do authors combine these rules? What is the multi-situation fusion rule? Is it related to the combination? The minimum value is sufficient for a complicated situation in which the road is congested and it is rainy?
4. The simulation did not show the situation of adverse weather conditions, although the relative rules are set. There are three rules, but only one rule is tested in the simulation. More simulations should be performed to support the proposed methodology.
Author Response
Please see the attachment.
Author Response File: Author Response.pdf
Reviewer 4 Report (New Reviewer)
I congratulate authors for their work and changes, However few minor changes are required:
1. Practical suggestions may be included in the Conclusion section based on study findings.
2. Following important citations may be included in Review Section:
a. DOI: 10.1007/s10668-022-02288-5
b. DOI: 10.3390/su13105523
3. Shuffle Sections 7 and 6. Conclusions section should come at last.
4. Explain more about Research Contribution and Novelty.
5. Double check spelling and punctuation errors.
6. Check the similarity index.
Author Response
Please see the attachment.
Author Response File: Author Response.pdf
Round 3
Reviewer 3 Report (Previous Reviewer 5)
Thank you for the effort to improve the manuscript.
For the previous question5, the authors should discuss this limitation in their conclusion.
Author Response
Thanks for pointing this out. We added the following based on your suggestion:
pp.17, lines 497 – 500
[Second, it is currently difficult to achieve simulation testing of adverse weather conditions and corresponding driving behavior analysis using VISSIM. Scenario development using driving simulation technology could be used to complete such experiments in the future.]
This manuscript is a resubmission of an earlier submission. The following is a list of the peer review reports and author responses from that submission.
Round 1
Reviewer 1 Report
Designing and simulating of a variable speed limit system for efficiency improvement of freeway bottleneck areas is researched in this paper. Two scenarios with different flow conditions are simulated and verified in VISSIM. The results can prove the theoretical reference of the variable speed limit system. The authors are suggested to explain the below two questions:
1 The system proposed in this paper gives the speed limit in bottleneck areas, please add discussion about how to determine the accurate speed for each vehicle.
2 The abstract is suggested to be condensed. The definition of bottleneck area should be explained in details.
Reviewer 2 Report
Comments are in the attached file.
Comments for author File: Comments.pdf
Reviewer 3 Report
- Everything looks good, the concepts explained in the paper are crisp and clear.
- The novelty and flow of the paper are good. - Overall the paper is good.
Use below papers as reference:
1. Mohd. Saifuzzaman, Syeda Farjana Shetu, Nazmun Nessa Moon, Fernaz Narin Nur and Mohammad Hanif Ali "IoT Based Street Lighting Using Dual Axis Solar Tracker and Effective Traffic Management System Using Deep Learning: Bangladesh Context" on 11th International Conference on Computing, Communication And Networking Technologies (ICCCNT 2020), July 1-3, 2020, IIT Kharagpur, West Bengal, India.
2. Mohd. Saifuzzaman, Nazmun Nessa Moon & Fernaz Narin Nur, “IoT Based Street Lighting and Traffic Management System” on IEEE Region 10 Humanitarian Technology Conference (R10-HTC), 2018, BUET, Dhaka, Bangladesh.
Reviewer 4 Report
The study aims to tackle the traffic congestion in bottleneck area by constructing a changeable speed limits system. The concepts, structures, and applications in a simulation scenario are presented in the paper. Although, it is an interesting and meaningful work, I have several concerns to the paper. Please see the comments below.
i) As stated in this paper, speed changes in bottleneck area are both vital to traffic delay and safety. This is because the speed or speed variation are generally viewed as a congestion index or safety surrogate measure. Accordingly, these contents could be highlighted in the Introduction section. Some literatures may help.
# https://doi.org/10.1016/j.physa.2021.126439
# https://doi.org/10.1016/j.trc.2021.103040
# https://doi.org/10.1016/j.aap.2022.106756
ii) In addition to AIMSUN, VISSIM, and SUMO, the software such as Transmodeler and Paramics are capable for serving the studies regarding speed change or congestion detection. These pieces of evidence may be used to enrich the literature review.
# https://doi.org/10.1016/j.trc.2014.08.001
# https://doi.org/10.1080/15472450.2014.936294
iii) It seems that 100% compliance of the drivers is hardly observed in reality. Whether it is possible to compare the simulations conducted with a compliance that is less than 100%? If this is difficult to be completed, please state this as a research limitation in the end of the paper.
iv) The flow speed (Table 3, without VSL system) of the scenario of 1100-pcu/h significantly decreases as time interval keep raising. What is the cause? I think the current discussion is not well organized because the speeds in scenario of 1100-pcu/h are quite different between simulations with and without VSL. Of course, I recommend the plot of the flow density over time in the two simulations.
v) The English writing needs to be thoroughly enhanced in the current paper. Please revise the words, phrases and sentences to see if they are proper and follow the logic.
Reviewer 5 Report
The manuscript discusses setting the variable speed limits. The contribution to this field is minor, and the major comments are as follows.
1. The logic in the literature review is weak, because the authors just listed papers. The need and gaps in the present research are not presented well in the literature review. Therefore, the contribution of this work is not clear.
2. Figure 3： draffic incident？Please explain figure 3 and the meaning of the numbers in the figure.
3. An algorithm is a set of rules that must be followed when solving a particular problem. The “algorithms” mentioned in the manuscript are more like some conditions rather than algorithms. Furthermore, what are the innovations of these “algorithms”?
4. What is the main difference between scenario 1 and scenario2 so that the authors needed to test both of them?
5. The example did not show the necessary of setting variable speed limits. It seems that its benefit is minor.
