Understanding Construction Logistics in Urban Areas and Lowering Its Environmental Impact: A Focus on Construction Consolidation Centres
Round 1
Reviewer 1 Report
Authors of the paper present results of surveys and simulations under The SUCCESS project. The subject of the paper is interesting and worth investigating but the methodology of the research is not fully understandable. It raises some doubts about the quality of the results and some issues require further clarification.
It would be appropriate to describe the assumptions for simulation studies, modelling and simulation processes including assumptions in COPERT software in terms of traffic modelling, e.g. traffic assignment in the network. The paper presents only numerical results of the simulation. It would be good to use graphic examples if possible (e.g. differences in the distribution of traffic in the road network between the scenarios). How has a reduction in the number of vehicles reduced congestion (a reduction in the number of vehicles is not the same as a reduction in congestion, which can be expressed, for example, by a change in the length of queues or delays)? Does CCC support only the indicated construction site or more construction sites within the city? Where was the CCC location established (e.g. how far from the central areas, from the construction site)? How were the economic savings calculated (table 4)? Is there an SUCCESS project report available that the authors refer to in their references?The information required is necessary to describe a methodology that is currently too short and unclear and makes it difficult to assess the reliability of the results and to identify the objectives of the research.
Author Response
|
Recommendation |
Status |
|
It would be appropriate to describe the assumptions for simulation studies, modelling and simulation processes including assumptions in COPERT software in terms of traffic modelling, e.g. traffic assignment in the network. |
Comment addressed: Summary of assumptions and simulation process have been described + reference to the detailed report of the simulations. |
|
The paper presents only numerical results of the simulation. It would be good to use graphic examples if possible (e.g. differences in the distribution of traffic in the road network between the scenarios). |
Comment addressed: a graph for the Truck arrival time on site has been added |
|
How has a reduction in the number of vehicles reduced congestion (a reduction in the number of vehicles is not the same as a reduction in congestion, which can be expressed, for example, by a change in the length of queues or delays)? |
Not addressed in the paper. A reduction in the number of vehicles should reduce the congestion but we agree that it is not systematic. This indicator was the only way to give an indication on the congestion in the project. Note that considering the scope of the scenarios, the impact on the length of queues or delays is quasi inexistent. |
|
Does CCC support only the indicated construction site or more construction sites within the city? |
Comment addressed in section 2. |
|
Where was the CCC location established (e.g. how far from the central areas, from the construction site)? |
Comment addressed in the sections 2 and 6. |
|
How were the economic savings calculated (table 4)? |
Comment addressed in section 2. |
|
Is there an SUCCESS project report available that the authors refer to in their references? |
Comment addressed in the paper and references |
Reviewer 2 Report
This paper deal with city logistic associated with the delivery of construction materials in urban areas. The topic is very interesting but explord not so well.
The authors propose an innovative logistics facility, named CCC, to improve the performance of the last leg of delivery of construction material. The core of the paper is the CCC, but the authors dedicate only a brief description of it, without justifying several crucial assumptions.
1) It is not clear what does “channeled before being consolidated” mean.
2) How did the authors decide to locate the CCC? Based on what assumptions? Did they test various locations of the CCC?
In large cities, the construction sites can be everywhere and the localization of the CCC could generate an additional cost for some zones.
The authors should define the number of CCC needed for each urban center and their localization. I would suggest using a stochastic optimization approach in order to generate several instances (construction site localization) and define the optimal CCC localization and the number of CCC needed.
The sentence “the CCC is close to urban centers” is not clear.
3) The authors defined different scenarios, based on which the extrapolate their results. How did they hypothesize the localization of the construction site?
4) It is not specified how the author calculated the reduction of congestion, the route optimization, and economic savings.
It seems to me that the main contribution of the SUCCESS project is reasonably high and complex, but the authors in this paper provided only some generic and approximate consideration.
In light of the above, I suggest to extend the work with relevant findings and start a new submission.
Author Response
|
The authors propose an innovative logistics facility, named CCC, to improve the performance of the last leg of delivery of construction material. The core of the paper is the CCC, but the authors dedicate only a brief description of it, without justifying several crucial assumptions. |
Comment addressed cf. following comments. |
|
1) It is not clear what does “channeled before being consolidated” mean. |
Comment addressed |
|
2) How did the authors decide to locate the CCC? Based on what assumptions? Did they test various locations of the CCC? In large cities, the construction sites can be everywhere and the localization of the CCC could generate an additional cost for some zones. |
Comment addressed in the section 2. NB1: The location of the CCC is determined among a given set of realistic options identified with the construction companies and/or the municipalities. So yes, different options have been considered. The methodology relies on a mathematical model of the stochastic facility location problem. NB2: The CBA take into account an average costs for renting a warehouse depending of the city. |
|
The authors should define the number of CCC needed for each urban center and their localization. I would suggest using a stochastic optimization approach in order to generate several instances (construction site localization) and define the optimal CCC localization and the number of CCC needed. |
Comment addressed in section 2 with more explanations on the definition of the scenario and the location of the CCC. We added a reference so the reader can have a more complete explanation on the methodology. |
|
The sentence “the CCC is close to urban centers” is not clear.
|
Comment addressed in giving an idea on the distance |
|
3) The authors defined different scenarios, based on which the extrapolate their results. How did they hypothesize the localization of the construction site? |
Comment already addressed in comment #11 |
|
4) It is not specified how the author calculated the reduction of congestion, the route optimization, and economic savings. It seems to me that the main contribution of the SUCCESS project is reasonably high and complex, but the authors in this paper provided only some generic and approximate consideration. In light of the above, I suggest to extend the work with relevant findings and start a new submission. |
Addressed with the other comments. |
Reviewer 3 Report
Thank you for this strong article on construction material logistics.
This article seems to focus primarily on simulated potential emissions and efficiency improvements from the implementation of CCC's. You should more explicitly state this in your introduction and abstract rather than saying the paper is about providing the more-vague concept of "better understanding."
Since this journal is titled "Sustainability," you need to add an explicit
explanation to your introduction of how this paper is related to the journal's core aim to "promote scientific predictions and impact assessments of global change and development." Your implication is connecting the tie between increasing global urbanization and increased construction with how CCC can address environmental challenges as well as the physical constraints to sustainable urbanization and (re)development. As this paper is currently written, it belongs in a construction journal rather than a sustainability journal.
Lines 37-40: Give more details on the "Horizon 2020 SUCCESS" project for readers who are unfamiliar with that project. Who is driving this project, who is affected, what kinds of activities is the project exploring or advocating for, etc.
Line 59: Explain more clearly why you feel these four sites are representative and what they are representative of (medium to large construction sites?) The clarity of this is obfuscated by the confusing wording of lines 57-59.
Lines 64 - 67: Elaborate on your simulation techniques and the functionality of Copert for readers unfamiliar with those techniques and software.
Lines 249-251: Give a more-detailed summary of how construction distribution is "barely comparable to other urban supply chains."
Conclusions and abstract: Provide some summary improvement numbers to quantify potential benefits of CCCs for traffic, shipment delays, emissions, etc. The environmental impacts are probably of greatest interest to readers of this journal.
Author Response
|
This article seems to focus primarily on simulated potential emissions and efficiency improvements from the implementation of CCC's. You should more explicitly state this in your introduction and abstract rather than saying the paper is about providing the more-vague concept of "better understanding." |
Comment addressed in adding another objective in the abstract. Note that the CCC is not the primary focus (it is only one section of the article) so we did not remove the “better understanding” which refers to the terminology used by the funding organization (European Commission) |
|
Since this journal is titled "Sustainability," you need to add an explicit explanation to your introduction of how this paper is related to the journal's core aim to "promote scientific predictions and impact assessments of global change and development." Your implication is connecting the tie between increasing global urbanization and increased construction with how CCC can address environmental challenges as well as the physical constraints to sustainable urbanization and (re)development. As this paper is currently written, it belongs in a construction journal rather than a sustainability journal. |
Title and abstract updated |
|
Lines 37-40: Give more details on the "Horizon 2020 SUCCESS" project for readers who are unfamiliar with that project. Who is driving this project, who is affected, what kinds of activities is the project exploring or advocating for, etc. |
Comment addressed in section 1 |
|
Line 59: Explain more clearly why you feel these four sites are representative and what they are representative of (medium to large construction sites?) The clarity of this is obfuscated by the confusing wording of lines 57-59. |
Comment addressed in section 2 |
|
Lines 64 - 67: Elaborate on your simulation techniques and the functionality of Copert for readers unfamiliar with those techniques and software. |
Comment addressed: Summary of assumptions and simulation process have been described + reference to the detailed report of the simulations. |
|
Lines 249-251: Give a more-detailed summary of how construction distribution is "barely comparable to other urban supply chains." |
Comment addressed in the conclusion |
|
Conclusions and abstract: Provide some summary improvement numbers to quantify potential benefits of CCCs for traffic, shipment delays, emissions, etc. The environmental impacts are probably of greatest interest to readers of this journal. |
A summary of findings from table 4 has been added |
Round 2
Reviewer 1 Report
Please provide a web link where I will be able to read the report "Simulation results; SUCCESS project, 2018; p. 231". I still do not have a clear picture of the modelling and simulation process.
Author Response
A link to the SUCCESS report on simulation results has been added in the references.
We do hope that editorial works (particularly on the references) will not remove these links.
In case they do, here are the raw links:
Reference 7 : Simulation results
http://www.success-urbanlogistics.eu/download/d4-3_simulation-results/?wpdmdl=4044
Reference 12 : Report on good practices in the EU and USA in construction logistics in urban areas
http://www.success-urbanlogistics.eu/download/d6-1_report-on-good-practices-in-the-eu-and-usa-2/?wpdmdl=3543
Reference 13 Mathematical programming tools for construction logistics optimisation problems
http://www.success-urbanlogistics.eu/download/d3-4_mathematical-programming-tools-for-construction-logistics-optimisation-problem/?wpdmdl=3450
Author Response File: 
Author Response.docx
Reviewer 2 Report
The manuscript has been revised according to reviewers’ comments. However, I have still some serious doubts about the optimization/simulation process.
It is fundamental for the clarity of the paper that the authors describe all the step of the simulation at least for one the four sites.
1) Illustrate on a map the initial set of location for the CCC – “determined among a given set of realistic options identified with the help of the construction companies 90 and/or the municipalities”–
2) The simulation should be based on: a) the initial set of possible location; b) random instances of construction sites. Next, the result of the simulation (travel times, pollutant emissions) should be the input data for the optimization procedure (optimal localization).
In lines 279 the authors state that after the optimal localization of the CCC they perform the simulation to compute times and emissions. But the optimal localization should be determined as a consequence of the network performances of the different scenarios (construction sites).
3) Finally, a new instance of possible construction sites should be used to validate your model and to compute the benefit of the CCC.
4) The details provided in lines 276-279 are too vague. Provide the mathematical formulation of the minimization programming.
Where should I read reference number 7?
Author Response
Dear reviewer,
Thank you for your valuable comments.
1) A figure has been added.
2) and 3) We have clarified the description of the simulation steps. Theses steps are however different from your understanding.
a) candidates CCC location data have been collected (algonside other data, like potential construction sites)
b) a first stochatstic optimisation of the transport flows has been computed in order to determine the optimal location for each site
c) then scenarios have been identified and simulated (demand, routing, pollutant emissions)
d) the results for each scenario have been compared to the baseline. An excerpt is presented in table 4.
4) In fact several optimisation models have been used at various simulation steps, and detailing all of them is note the scope of our paper. A new reference (13) has been added to the project report that details the required mathematical formulations.
In response to your last point (unnumbered) a link has been added to the reference, to easily find the references SUCCESS deliverables and in particular the reference 7. In case these links get removed by the editorial process before our final review, please find theme hereafter:
Reference 7 : Simulation results
http://www.success-urbanlogistics.eu/download/d4-3_simulation-results/?wpdmdl=4044
Reference 12 : Report on good practices in the EU and USA in construction logistics in urban areas
http://www.success-urbanlogistics.eu/download/d6-1_report-on-good-practices-in-the-eu-and-usa-2/?wpdmdl=3543
Reference 13 Mathematical programming tools for construction logistics optimisation problems
http://www.success-urbanlogistics.eu/download/d3-4_mathematical-programming-tools-for-construction-logistics-optimisation-problem/?wpdmdl=3450
Reviewer 3 Report
Figure 1 colors = replace green with blue or use a different texture to make the chart legible to color-blind readers.
Footnote 7 in particular and most footnote in general need more-specific source information. Can you provide URLs?
Author Response
Dear reviewer,
With regards to your first comment, the color schema of Figure 1 has been updated, with a color schema suitable for color-blindness.
With regards to your last comment, the direct links to SUCCESS project deliverables have been added in the references (reference 7, 12 and 13). All other references can be found through online libraries. In case hyperlinks are removed by editorial process before our final review, we provide here the raw links.
Reference 7 : Simulation results
http://www.success-urbanlogistics.eu/download/d4-3_simulation-results/?wpdmdl=4044
Reference 12 : Report on good practices in the EU and USA in construction logistics in urban areas
http://www.success-urbanlogistics.eu/download/d6-1_report-on-good-practices-in-the-eu-and-usa-2/?wpdmdl=3543
Reference 13 Mathematical programming tools for construction logistics optimisation problems
http://www.success-urbanlogistics.eu/download/d3-4_mathematical-programming-tools-for-construction-logistics-optimisation-problem/?wpdmdl=3450
Author Response File: Author Response.docx
Round 3
Reviewer 2 Report
The authors have addressed my comments, and the paper now provides important technical details that were previously neglected.
Author Response
Dear Reviewer,
Thank you for your feedback.
The authors
