Energy Saving Potential of Traffic-Regulated Street Lighting
Round 1
Reviewer 1 Report
The authors present a case study carried out on a road section of a Hungarian town. This includes the description of a simple methodology of measuring and analysing traffic data and estimate the energy saving potential of sensor regulated dynamic lighting and the less expensive preprogramed time control.
This research is interesting and timely.
The following are my observations:
1. Quality of technical presentation;
· The presentation of your contribution at the end of the introduction section is very scanty.
· Your main contribution should be well stated at the end of the introduction section including the main differences between your work and the previous works in literature, if there is any.
· In section 3.2, it will be good to add some sentences that will define UTC+1 and UTC+2 time zones
2. Results presentation;
The results are presented in a good way
3. Originality and Significance of contribution to the area of research;
The idea is very good and timely. However, no comparisons with what is available in the literature. The literature review within the introduction section should be added with some relevant publications, or a new section (Related work) should be included.
4. Appropriateness of Citations and Referencing;
The Citations and Referencing is OK. However, cross check the reference No. 29
5. Presentation quality - including Equations, Graphics, Tables, etc.
Equation 1, 2 and 3 are presented without any citation. If they are not originally your equation you should acknowledge their original sources by citation.
Author Response
Response to Reviewer 1,
Thank you for your useful comments and suggestions aimed at improving the quality of the paper. In the following I summarize the actions taken based on your instructions:
1. Quality of technical presentation;
- The presentation of your contribution at the end of the introduction section is very scanty.
- Your main contribution should be well stated at the end of the introduction section including the main differences between your work and the previous works in literature, if there is any.
Response 1. The Introduction was reworked according to your proposals.
2. In section 3.2, it will be good to add some sentences that will define UTC+1 and UTC+2 time zones
Response 2. Section 3.2 was extended with explanatory sentences and a reference to the ISO 8601 standard. Lines 309-310
3. The idea is very good and timely. However, no comparisons with what is available in the literature. The literature review within the introduction section should be added with some relevant publications, or a new section (Related work) should be included.
Response 3. The Introduction was extended with additional references to related work. New sentences were inserted to highlight the novelty of the manuscript.
4. The Citations and Referencing is OK. However, cross check the reference No. 29
Response to 4. The reference was corrected and updated.
5. Equation 1, 2 and 3 are presented without any citation. If they are not originally your equation you should acknowledge their original sources by citation.
Response to 5. The equations are original, but the curve fitting method employed is commonly used therefore I have included a general statistical reference for readers interested in the details of the calculation.
Reviewer 2 Report
Review Report Manuscript sustainability-2306204
Manuscript Number: sustainability-2306204
Journal: MDPI Sustainability
Article Type: Article
Title: Energy saving potential of traffic-regulated street lighting
Dear Colleague,
Thank you for the article you submit to MDPI Sustainability. Your article deals with the measurement of energy savings according to the type of luminaire by presenting mainly two modes of operation: a simple solution of extinction / ignition and a “smart” solution with sensors.
Your article is interesting and well written. I have quite a few comments.
In your introduction, you address the subject in relation to the energy crisis, which is very good. But urban lighting also concerns a few other topics that you could address in your introduction, in particular light pollution. Indeed, some publications dealt with public lighting shortly before this crisis and it is a subject that remains topical:
C. D. Gãlãţanu, L. Canale, D. D. Lucache and G. Zissis, "Reduction in Light Pollution by Measurements According to EN 13201 Standard," 2018 International Conference and Exposition on Electrical And Power Engineering (EPE), Iasi, Romania, 2018, pp. 1074-1079, doi: 10.1109/ICEPE.2018.8559722.
Another point that could be interesting to highlight in your study concerns energy savings. A table presenting the savings resulting from a simple “extinction / ignition” system and the more advanced system would also be interesting to present.
The question of environmental impact also arises. Only life cycle analyzes can provide an answer. Because if the increase in the technological level can allow additional energy savings, it also has a greater impact on the environment, not to mention an increase in the risk of breakdown. I invite you to consult Kevin Bertin's thesis which deals with life cycle analyzes on urban lighting:
https://www.theses.fr/2022TOU30071
I will now go over a few small points to discuss in your article:
Line 179; Table 1:
Many parameters in your array are constant. It therefore does not seem useful to present them here. Taking these parameters out of the table and presenting them with some explanation in the text would be nice.
Line 288: “grouped” (not “groped”)
In your conclusion, could you give a reminder of the % energy savings achieved (on average) according to the different types of technologies.
Conclusion: your article is very interesting. Thank you for taking into consideration the few small remarks I propose.
I suggest that this article be accepted for publication.
Comments for author File: 
Comments.pdf
Author Response
Response tp Reviewer 2 Comments
Dear Reviewer 2. I do appreciate your supportive comments and suggestions to improve the quality of the paper. Please find below the list of actions based on your instructions.
1.
In your introduction, you address the subject in relation to the energy crisis, which is very good. But urban lighting also concerns a few other topics that you could address in your introduction, in particular light pollution. Indeed, some publications dealt with public lighting shortly before this crisis and it is a subject that remains topical:
Response to 1: The introduction was extended with a paragraph highlighting the environmental impact of light pollution. (Lines 44-49) References 6-8 were inserted as backup information for the reader.
2. Another point that could be interesting to highlight in your study concerns energy savings. A table presenting the savings resulting from a simple “extinction / ignition” system and the more advanced system would also be interesting to present.
Response 2: Table 4 summarizes the energy saving options for all the four cases investigated. This table was updated according to the request of another Reviewer.
3. The question of environmental impact also arises. Only life cycle analyzes can provide an answer. Because if the increase in the technological level can allow additional energy savings, it also has a greater impact on the environment, not to mention an increase in the risk of breakdown. I invite you to consult Kevin Bertin's thesis which deals with life cycle analyzes on urban lighting
Response 3: Thank you for rising my attention to the LCA publications. I have included a short paragraph about the need for LCA as a potential continuation of this work and included references [35-36] from lighting specific LCA studies. Though these publications focus on indoor lighting, the methodology may be extended for outdoor systems.
4. Line 179; Table 1: Many parameters in your array are constant. It therefore does not seem useful to present them here. Taking these parameters out of the table and presenting them with some explanation in the text would be nice.
Response 4. Table 1 was simplified according to your instructions.
5. Line 288: “grouped” (not “groped”)
Response 5. Spelling error has been corrected.
6. In your conclusion, could you give a reminder of the % energy savings achieved (on average) according to the different types of technologies.
Response 6. The Conclusion was shortened and energy saving figures were incorporated in the revised section.
Reviewer 3 Report
The topic of the manuscript is consistent with the area of interest of the journal. Editorial and substantive errors were detected in the manuscript, which should be corrected. The weakness of the manuscript is the lack of analysis of errors and areas of uncertainty of the performed calculations and measurements. A list of my most important comments and doubts that the authors should address is listed below.
1. The summary of the chapter "Introduction" should show the novelty and originality of the work and what literature gap the manuscript presented by the authors fills.
2. I recommend creating a "Nomenclature" section in which all symbols and abbreviations used in the manuscript should be listed. Please complete it.
3. The substantive description of Figures 4a and 4b is insufficient. One sentence is not enough. There is no analysis of the obtained results here. Please complete it.
4. Figure 5 is illegible. It should be made so that it is also legible in black and white, e.g. change the symbols in the legend.
5. No description of Figure 8 in the manuscript. Please complete it.
6. There is no section on error analysis and areas of uncertainty in the manuscript. Please complete it. 7. The "Conclusions" section should be short and contain the most important quantitative and qualitative research results obtained by the authors. Please correct it.
8. Would it not be simpler and cheaper to use a system consisting of motion sensors, dusk sensors (reacting to changes in insolation) and radiation intensity (light flux) than the system proposed by the authors? Please make a comment.
Author Response
Response to Reviewer 3 Comments
Dear Reviewer, Thank you for your useful comments and suggestions to improve the quality of the paper. Please find below my responses to your comments:
- The summary of the chapter "Introduction" should show the novelty and originality of the work and what literature gap the manuscript presented by the authors fills.
Response to 1: I have reworked the Introduction to better highlight the literature gap. My key point is: Majority of publications in the field of smart street lighting have focused on the technology connecting lighting equipment with sensors and controllers. The energy saving figures reported are specific for a certain installation, but there is no direct information on the performance of competitive solutions under the same traffic conditions.
- I recommend creating a "Nomenclature" section in which all symbols and abbreviations used in the manuscript should be listed. Please complete it.
Response 3: The nomenclature was created and presented as Supplementary Material Table S1.
- The substantive description of Figures 4a and 4b is insufficient. One sentence is not enough. There is no analysis of the obtained results here. Please complete it.
Response to 3: The description of Figure 4 was extended with analysis and interpretation of data.
- Figure 5 is illegible. It should be made so that it is also legible in black and white, e.g. change the symbols in the legend.
Response to 4: The symbols were changed to line style markers to better visualize differences between the upper and lower ends of the distributions.
- No description of Figure 8 in the manuscript. Please complete it.
Response to 5. The missing reference for Figure 8 was inserted in the text with additional explanation.
- There is no section on error analysis and areas of uncertainty in the manuscript. Please complete it.
Response to 6. The text was extended by paragraphs, addressing two aspects of errors: a) False object identification. Section 2.1 describes that very small difference was observed between manual automatic traffic counting. b) Over-illumination or under-illumination relative to the requirements of the actual traffic conditions. The Table 4 was extended with under and over illuminated hours related to each control mode. Addition information is provided in the new Discussion section partly dedicated to the error of the control method.
- The "Conclusions" section should be short and contain the most important quantitative and qualitative research results obtained by the authors.Please correct it.
Response to 7: The Conclusions was shortened, highlighting the most important quantitative and qualitative information only.
- Would it not be simpler and cheaper to use a system consisting of motion sensors, dusk sensors (reacting to changes in insolation) and radiation intensity (light flux) than the system proposed by the authors? Please make a comment.
Response to 8: There are standalone and networked control solutions in the market and both have their advantages and disadvantages. Motion and light sensors may be integrated into a luminaire establishing autonomous luminaire control. This approach is used mainly for pedestrian zones or bicycle roads. The advantage is very high responsiveness and good energy saving potential at a moderate increase in investment cost. The disadvantage is that on the same road section there are continually evolving full power and dimmed or OFF states. The fluctuating light level may be disturbing to the neighborhood. If there is no communication between the luminaires, good visibility is restricted to the detection range of the motion sensor. For high speed motorized traffic networked lighting control ensures road illuminance uniformity. The dawn side is less energy saving or higher investment.
This reasoning was incorporated into the Introduction section.
Round 2
Reviewer 1 Report
All comments have been addressed
Reviewer 3 Report
The authors addressed all my comments and concerns. In my opinion, the manuscript contains the necessary elements of a scientific paper. Hence, I recommend this work for publication.
