Specifics of Creating a Public Transport Demand Model for Low-Density Regions: Lithuanian Case

Round 1

Reviewer 1 Report

Comments and Suggestions for Authors

please see the attached file.

Comments for author File: Comments.pdf

Comments on the Quality of English Language

 it is fair. 

Author Response

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Author Response File: Author Response.pdf

Reviewer 2 Report

Comments and Suggestions for Authors

The article titled “Principles of creating a public transport demand model for low density regions: Lithuanian case” describes the model preparation of traffic demand in Lithuanian region. Article itself is quite interesting but is missing many sufficient issues that has to be taken into consideration before publishing. I have made a list of my comments and remarks.

General remarks:

1)     I would recommend to change the title of the article. It is hard to say that it shows “principles” of creating public transport demand model. I would rather suggest “calibration and/or verification”. This opinion was based on article structure and conclusions.

2)     There is clear hypothesis missing in the text.

3)     The literature is insufficient, poor and rather old. I think that authors should think about something more up-to-date as well as to enrich the article with more foreign and valuable articles, also while explaining important topics included in the text, for instance , line 113 – needs proper and valuable citations, line 77, line 119 (description of gravity model). And the references also need to be checked as they are not unified.

4)     What is “elderhip” – I haven’t found the explanation of this term.

5)     Conclusions are more than obvious. They don’t bring any new terms or knowledge. Those conclusions could be prepared without any model. The model should be the main point of conclusions- it needs rewriting. The model itself wasn’t sufficiently described. I feel high lack in this field.

6)     The article needs rewriting. Some terms and data are not introduced in text. Come from nowhere, the disappear at other chapters. It is hard to follow. I would be good to provide: 1. Introduction, 2. State-of-the-art, not only in Lithuanian regions, but in other countries (data about modes of transport), 3. Introduction to Lithuanian case, 4. Explanation of modelling, 5. Presentation of findings of the research 5. Conclusions

Detailed remarks

1)     Line 37-38 – it would be good to describe in details the scope pf transport modelling. Only macroscopic modelling was mentioned, but not in the right way. It is not the area of PT that describes the scope of modelling, rather the modelled elements. Maybe it would be worth trying description like: “Two types of models are used in traffic modelling: micro and macroscopic. Both types of models differ in the way they take into account vehicles in the flow and the description of their movement. Microscopic models require modelling of the dynamics of movement of individual vehicles and interactions between neighbouring vehicles. However, in macroscopic models, vehicles are treated as a stream with detailed description using intensity, density and speed.”

2)     Line 39, I would not recommend to add “without the need to invest in pricey equipment.”. Programs that provide modelling in transport are not cheap. Some institutions cannot afford full scope of this kind of programmes. You have mentioned PTV tools (including VISUM) in the article, and this particular programme is quite expensive. I would recommend to delete this part of a sentence.

3)     Lines 49-52 – I think this paragraph can be deleted, as the structure of the article has been provided in the abstract at the very beginning.

4)     Lines 54-57 – this part needs redrafting as it doesn’t sound good. The description of PTV VISUM should be more understandable.

5)     Line 77 – mentioned source no. 12 “Tauragė Sustainable Mobility Plan” couldn’t be found in the Internet. It would be better to include sources that could be checked and furthermore – different type of sources showing the scale of travel modes. I understand that this data is included in the article in following paragrapf, but in this part, I recommend to do in-depth research for similar data in other countries. This data is not sufficient. And we also have no explanation, why this mobility plan was included. This is important part of the research that needs improvement. If the authors plan to concentrate on specific area/city/region – it has to be introduced and explained in the text.

6)     Line 101 – The term “OD matrix” needs to be described. It came out of nowhere in the text, but still, it is important, as it has been included also in keywords.

7)     Lines 132-135 – this paragraph needs redrafting. Authors use interchangeably terms like “transport mode/transport system” explaining demand model. It should refer directly to reference units, like: bus, tram, subway, pedestrian, cyclists etc. And then explained, which units are taken into consideration as for PT included in the model (does it include subway, trams – not always, but we don’t know that). Therefore I recommend to include proper references explaining the elements of demand modelling.

8)     Line 146 – I would update and enrich the references and literature used in description of traditional planning model assignments. There is only one source in this part and comes from 2001.

9)     Equation 6 and 7 needs either source origin (citation) or explanation that it was prepared by the authors.

10)  Line 221 – first sentence needs to be checked- it doesn’t sound good. I would also recommend to put the paragraph from lines 221-230 way up in the text. For instance- somewhere along “modal split” or “assignment” chapters, as Taurage was already mentioned in the text before. This is a bit mixed up- needs redrafting.

11)  Line 220 – it should be explained what modes of transport are taken into consideration under PT. This has not been explained. Maybe it should be somehow included in city description or any other proper place. Only public transport carriers were described which I find insufficient.

12)  Line 259 – It should be written that “Table A2” is included as an Appendix A. This is unclear in the text.

13)  Line 331 – explaining “GEH” should be based on specific sources and proper citation. This paragraph needs to be enriched.

Comments on the Quality of English Language

English is fine, but still, the whole article needs editing and proper division into sections and presented content. You need to tidy up the structure of the article

Author Response

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Author Response File: Author Response.pdf

Reviewer 3 Report

Comments and Suggestions for Authors

The basic problem of the system description of transport in urbanised areas is the characterisation of the elements and relations which make up the land-use structure and the structure of the transport system. This structure gives rise to transport needs which are the demand for transport, as well as shaping the supply of transport in the form of the transport system and its transport potential. It is also itself subject to change (mainly long-term) as a result of interactions between: changes in the quality of transport services and changes in transport accessibility, changes in the demand structure and changes in user mobility, changes in residential activity linked also to the availability of land for certain economic activities or housing. To describe traffic in a transport system, mathematical models are used mathematical models, adapted to the required level of detail of the representation of transport phenomena. On the one hand, these can be models used at the planning stage that operate on global and aggregated values. On the other hand, when a very detailed detailed description of traffic flows is required, microsimulation, deterministic and probabilistic models are used. and probabilistic models, often using fuzzy set theory and genetic algorithms. The article fits into this premise. However, I have a couple of threads that would need to be completed.

1. The article does not contain an explicit chapter on literature research and reference to the global body of literature on the themes raised above. 

2. The conclusions section does not include a discussion and limitations of the results obtained. 

Apart from these comments, the article meets the requirements of the publisher in which it is to be published.

Comments on the Quality of English Language

The quality of the language used in the article does not raise any major objections, but a re-check of the article by a native speaker is required.

Author Response

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Author Response File: Author Response.pdf

Reviewer 4 Report

Comments and Suggestions for Authors

Poor literature review. The introduction must be updated with references linked to the paper's goal. 

The Introduction part is missing the goal of the paper. Please add.

Terminology: I suggest using Transport zone, instead od Traffic zone.

Chapter 2.1. Trip generation.

What is for you "a large number of person groups" (Line 67)? Please specify.

How did you define the models for production and attraction, models (1) and (2)? Please explain why you use the number of residential houses and apartments are variables. What if the house/apartment is empty? What about the number of inhabitants? Moreover, you have talked about different person groups, but you fail to use any, or am I wrong? What about other factors: number of working places, number of students per school, number of employed, number of students per resident place, GDP, motorization rate, ... Did you consider any of these, and if yes, why are these omitted from the final model?

Moreover, you fail to give some initial data. How many transport/traffic zones do you have? 

Chapter 2.2. Trip distribution. You only present a general Gravity model, are there any specifics in your model, please highlight and explain.

Chapter 2.3. Modal Split. I understand that only PT is modeled, but if so, then the trip generation model must be more focused on attributes affecting PT usage, and the number of houses/apartments certainly is not enough. This is in addition to my comment on trip generation.

Chapter 2.4. Assignment. The text is confusing, you start with a general assignment, then opt for a timetable assignment and describe the assignment model. 

All text lines 155-182 should not be here. These results have no relevance to the assignment model. This could be used in the trip generation model. You have important data, like the percentage of population not using PT due to having access to a car and similar, please use these in the trip generation model. Some other outputs of the survey are not even relevant to the generation model, but are important for network improvement, providing new service trips, etc. Use these accordingly and please leave any survey date for later chapters where you give the case study application for the Taurage region.

Chapter 3. What is eldership? It must be a misleading translation. Please correct.

3.1. Trip generation. Here you mention the factors I have been talking about in my comments, but you fail to give an exact model. Please give a model for each trip group, H-W, W-H, etc. How did you calculate the combined function parameter values given in Table 1?

3.2. Trip distribution

Do you use the same combined function graph for H-E, E-H, H-S, and S-H trip models? You give only one Figure 1.

You still fail to give the number of traffic zones in the text. You do have it in the annex. Please rewrite and give the basic data, also refer to the tables in the annex so the reader can get a better insight into your research.

3.3. PT Assignment

Figure 2 I missing the unit for passenger flow. Is it passengers per month? If yes, values are significantly low. Moreover, the figure itself does not show what you stated about the long distances to PT stops. This could be better shown by the stop catchment areas, isochrones, or similar. 

Figure 3 is also missing the units, and also legend with the names of the blue and green bars. 

You also mention GEH, but you fail to give the values of your calculations. Please add.

Why do you give basic principles ate the end of the 3.3. It has no relation to the trip assignment. It is for the overall model. From my point of view, these could have been given and the beginning of the model presentation. First you give principles, the present the model, and then give a numerical example for the region you selected.

 

To conclude, what I am missing here is the purpose and usability of the model. How can you improve PT with this model? You have given some comments about the low service levels, long walk distances, lack of vehicle trips, and similar, but you need to reflect these directly through your model. Moreover, the applicability of the model in other regions is not clear. You give models and values for your region but fail to explain how can a reader apply them somewhere else. What he/she needs to do, no clear steps, recommendations, etc. are given. This adds value to your research because the low-density area PT models are important.

 

Author Response

Please see the attachment.

Author Response File: Author Response.pdf

Round 2

Reviewer 2 Report

Comments and Suggestions for Authors

Dear Authors,

 

Thank you for your detailed response. You have made a major revision of the article and include sufficient changes. Now it is, in my opinion, prepared properly. Well done. I have no further remarks.

Author Response

Dear Reviewer,

We are very grateful for your time spent reviewing and commenting on our paper.

Reviewer 4 Report

Comments and Suggestions for Authors

First, thanks to the authors for responding to the previous comments. I see that the majority of the comments are accepted and the paper is improved. However, I still have a few doubts regarding the methodology, it seems that we do not understand each other well.

Replying to my Comment 5: How did you define the models for production and attraction, models (1) and (2)? your Response 5 was: Thank you for your comment. I don’t use the number of residential houses and apartments, I use population data (number of inhabitants). More than one population group is used: „In order to create the Green Region OD matrix, demographic and statistical data were collected, such as the number of the working population (WP), the number of jobs (J), the number of students and school children (SCH), the capacity of educational institutions (inhabitants from 7 to 30 years old) (EI), the number of pre-school children (CH), the capacity of pre-schools (PSCH) (children up to 7 years old). Demographic and statistical data was collected to determine the output and attraction of passenger flows and is presented in the Table A1 that is included as an Appendix A“ (391-398 lines). It was taken into account and not omitted from the final model.

I agree that you gave the data in the Appendix, but I still don't see how this data is used in models 1 and 2. Please explain this and also in the numeric example provide us with numeric values of the production and attraction factors for each variable and each zone. This must be added.

My Comment 17: You also mention GEH, but you fail to give the values of your calculations. Please add. Your Response 17 included: Information about GEH statistics is added. I have moved this literature review to the subsection 2.5 (326-344 lines). This is ok for model description, but I expected of you to give the exact values in the numeric example, not general GEH data.

In replying to my Comment 18, you stated: Response 18: Thank you for your comment. The text have been clarified. The basic principles of developing a PT demand model are described in Chapter 2. The article highlighted the main specifics in the regions of developing demand models and described the main suggestions for creating a PT demand model in the regions that consist of low-density areas (last paragraph of section 5).

You have added a new chapter 5. Presentation of findings of the research, but you are presenting Visum outputs in the first part of that chapter. Then you give 5.1. Model calibration and validation but this is not the presentation of the finding, validation and calibration are an essential part of the modeling process, you present results after you calibrate and validate.

You have edited figures 3 and 5, but I still strongly suggest exploring and including other graphical presentations of the results, because existing figures are not clear and do not adequately represent the findings you give in the text.

Moreover, in the same chapter 5.1. you present main suggestions, but it has nothing to do with calibration and validation.  I strongly suggest restructuring this part, maybe to create a new chapter for these suggestions, as this is very important and I have highlighted this in my comment 19.

 

Author Response

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Author Response File: Author Response.pdf