Exploring Generational Private Mobility Paradigm Shifts through Duration Modeling Analytics: A Greek Case Study

Round 1

Reviewer 1 Report

This paper aims to explore the mobility milestones in Greece and identify the factors that affect them. The authors examine it through five archetypes of mobility and using duration modelling. The models developed considers Kaplan-Meier and Cox Proportional Hazards models. Authors suggest that highlight the mobility profiles shift and the specific factors responsible for those changes are helpful to predict future trends and gain a better understanding of mobility issues and challenges, allowing for a more future-proof, long-term, and robust transport planning. Results show that mobility paradigms are evolving and are affected by a wide array of factors like age, parent’s household income during their first years of adulthood, and the environment in which someone grew up.

Also, the method estimates the shifting probability (or not) of mobility milestones related to explicative variables. Data were collected out from 316 questionnaires.

This paper contains many things that are not easy to understand. It is tough to follow the paper, the explanation is not clear, and “forgets” many specifications. Therefore, judging its quality or the correctness of the methods used is problematic. The title and abstract promise content are not realised, reducing expectations. Moreover, the literature is not enough to justify the choices made.

 

The main drawbacks are reported in what follows, divided into major and minor suggestions:

Major comment 1

The title “Exploring generational mobility paradigm shifts in Greece through duration modelling analytics” does not reflect paper contents. First, it suggests that the analysis considers ‘mobility’ at all, private and public, but it analyses private cars, motorbikes, bicycles, and travels by airplane. Therefore, the principal focus is private mobility. Secondly, the title suggests that the analysis regards Greece evaluation, but the data considered are too few (311 questionnaires compared to 10.7 million habitants) to affirm such a thing.

It is required to change it.

 

Major comment 2

Line 103-105, authors say: “The concurrent effect of the economic crisis, the increased reliance on private mobility, along with the rapid evolution societies are undergoing in a global lever, render the case Greece's case study particularly interesting”. This sentence needs clarification. On what basis is this affirmed? In addition, the economic crisis’s effect may have had repercussions on the relevance of the factors (e.g., worse in the quality and quantity of public transport and the consequent increase in private motorization?).

 

Major comment 3

Line 107-111. I am perplexed about these ‘mobility milestones’. How and why did you select them? Is it a choice that comes from a literature review? This 'top-down' decision proposed in this way has no scientific evidence. It needs to be further strengthened; e.g., it does not consider public transport, cycle mobility is evaluated only for adults, etc. The first example could be solved by circumscribing the field of study better (i.e., previous comment on title and abstract).

 

Major comment 4

Line 114-117, authors say: “Duration analysis has been deemed most appropriate, since it can take into consideration all the above-mentioned information and is a statistical branch highly specialized in period analysis and has many advantages compared to more generic statistical tools”. What are these advantages? What about the disadvantages? This assertion needs to be clarified here or moved (to be clarified anyway) to section 2.1.

 

Major comment 5

In section 1, a summary of the structure of the paper is entirely missing.

 

Major comment 6

This paper is not clearly motivated. There is a concise discussion in the introduction, but it is difficult 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. That brings me to the question of what the contributions of your work are, which are not clear and well-established. What do authors propose as opposed to the current literature? Are the authors strictly relying on the existing literature? Did they propose some novelties? Are they proposing something new? I do not find any answer to these questions throughout the manuscript.

 

Major comment 7

Line 181-183, authors say: “Similar to other types of statistical analysis, we perform duration analysis under the assumption that apart from the explanatory variables, taken into consideration, all other parameters that affect the duration examined are considered equal”. What are these explanatory variables? How did you choose them? A better explanation should be required. In my opinion, that is very relevant. Also, a reference for this knowledge seems necessary here.

 

Major comment 8

In Section 2.2 authors explain that data derived from a questionnaire from which they collected 316 answers. In my opinion, it requires a major revision in terms of questionnaire explanation. Was it anonymous? How were the questions structured? Were the questions open or closed? Was it done in several steps?

In addition, the reply to the questionnaire for a national trend is few (see major comment 1). To make the calculation more effective, wouldn't it be better to adopt a Monte Carlo simulation?

Moreover, have a look at this paper that had the same problem and solved it through a Monte Carlo simulation:

• Barabino, B., Cabras, N.A., Conversano, C. et al.An Integrated Approach to Select Key Quality Indicators in Transit Services. Soc Indic Res 149, 1045–1080 (2020). https://doi.org/10.1007/s11205-020-02284-0

 

Major comment 9

Section 3, from lines 249 and 281. More than a result, this is the method. I suggest moving it to the previous section.

 

Major comment 10

Line 282-291. In my opinion, this introduction of section 3.1 justifies the results even before the elaborations. Therefore, it appears to be disconnected and/or self-justifying. I would move it below to justify the data results.

 

Major comment 11

Line 302-303, 376. Authors speak about “explanatory variables that appeared to greatly affect…”.   Why are there some that have been excluded as not relevant? How and why did you exclude them? Likewise, throughout the contribution, I wonder how certain factors were chosen for the five ‘mobility milestones’ (e.g., line 355-357 “Choosing to buy a used or new car, has been successfully linked with a variety of factors, like income, employment status, the area of residence and more.”).

Only in the conclusions (section 5, line 583-586) do we discover that some factors were deemed insignificant. However, even here, it is not clear how.

I think it is essential to explain it right away, why and how.

 

Major comment 12

Section 3.4 authors say: “Some examples are correlations between bicycle usage and related infrastructure, socio-economic characteristics of the general population of an area, the safety cyclists perceive during their transport, duration of an average bicycle route and more [61].” The article cited investigates only the determinants for commuting to work. Thus, some factors they are not considered; e.g., the topographical features on which the use by users such as children, the elderly, and adults with motor or respiratory problems depends.

A reference improvement for this knowledge seems necessary here.

 

Major comment 13

Line 455-456 authors say: “One of the reasons is the unfavorable to cyclists condition of Greek infrastructure [63], 455 which can also be observed by less bicycle sales in Greece [64].” If it is in relation to the existing infrastructures, how can it be in reduction? I am perplexed about this sentence, please clarify it.

 

Major comment 14

Line 457-460. The possibility that the interviewer getting the first bicycle at 18 does not convince me. This assessment is a bit strange at this age if it is not first compared with minors’ data. Why at 18 years old and not before? Please clarify it.

 

Major comment 15

Line 481-484 authors say: “Those results show an increasing trend of younger generations shifting towards preferring sustainable, human-powered transport modes. Green directives and sustainable mobility policies are a mechanism that could have made this change possible [65].” Is this only deduced with the age factor? Couldn't it also be due to less economic independence or the high cost of cars?

In this case, I wonder how the factors that influence the so-called five ‘mobility milestones’ were chosen.

 

Major comment 16

Line 492-495 author say: “A possible explanation is that those whole grew up in villages had a bigger need of having a reliable private transport vehicle, due to living in remote areas, that are less frequently covered by public transport [58,59].”  In my opinion, it depends on the travel distance. It would make more sense for those who live in the villages to equip themselves with motorized vehicles. Just as it is easier to use bicycles in cities.

 

Major comment 17

In section 5, line 629-632, I believe that the method’s limits should be expanded, and those of calculation should be considered.

 

 

 

 

-----------------------------------------------------------------------------------------------------------------------------------------------

Minor Comment 1

The layout of Table 1 makes reading difficult. The alignments of the different lines, without separations between the "variable name" make it difficult to understand the correspondence between the “variable name”, “levels”, and “percentage”. I think it needs to be rearranged.

 

Minor Comment 2

The layout of Table 2 makes reading difficult. I think it needs to rearrange the alignments of the different lines.

 

Minor Comment 3

Line 302, 368, 415:  “The figures in Figure”.

Minor Comment 2

A minor revision of the English is required. There is some grammar mistake in line 28, 41, 51, 56, 58, 72, 104, 127, 264, 267, 268, 275, 281, 312, 316, 317, 353, 406, 429, 455, 485, 524, 571, 582, 605, 632, 634.

 

 

 

 

Author Response

Please see the attachment.

Author Response File: Author Response.pdf

Reviewer 2 Report

Dear editor and dear authors,

Thank you for this assignment and this interesting read respectively.

The paper is a worthwhile piece of research that deserves to be published. Is a ‘return’ to checking out some of the basic elements underpinning travel behaviour and modal choices. These days we forget (by looking into all these emerging mobility technologies) that seemingly simple decisions early in humans’ lifecycle define their travel behaviour profiles permanently. I found the notion behind the paper worthy of investigation and the presentation of findings satisfactory.

To help the authors improve their contribution to the field I will provide some advice; following these few simple steps will lead them to a truly impactful manuscript.

1. The introduction works fine. I like the explicit identification of the key research aim. I need a final paragraph in the introduction describing the paper’s structure.

2. The literature coverage is relatively okay but can be somewhat improved with some minor light touches. Let me offer some recommendations that for different purposes each fit in making the rationale of the paper better.

Nikitas, A. (2018). Understanding bike-sharing acceptability and expected usage patterns in the context of a small city novel to the concept: A story of ‘Greek Drama’. Transportation research part F: traffic psychology and behaviour, 56, 306-321.

Clark, B., Chatterjee, K., & Melia, S. (2016). Changes in level of household car ownership: the role of life events and spatial context. Transportation, 43(4), 565-599.

Clark, B., Chatterjee, K., & Melia, S. (2016). Changes to commute mode: The role of life events, spatial context and environmental attitude. Transportation Research Part A: Policy and Practice, 89, 89-105.

Sigurdardottir, S. B., Kaplan, S., Møller, M., & Teasdale, T. W. (2013). Understanding adolescents’ intentions to commute by car or bicycle as adults. Transportation research part D: transport and environment, 24, 1-9.

3. Some figures are so small that are difficult to read. Consider making some pages horizontal and enlarge the figures accordingly.

4. Is your sample for the quantitative survey enough and why is that? I need just a line or two to confirm that by citing studies using a similar number of respondents.

5. Can you present the key descriptive/numerical results in the form of a table in an Appendix?

6. The discussion part needs a slightly better reference engagement. Can you add a few more cases (3-4) when you benchmark some of your findings against relevant literature findings?

7. Add a sentence about future research.

Other than that I can say that the analysis offered is very fine and well visualised. The paper draws some important conclusions and acknowledges its limitations.

These few amendments will allow the revised paper to be super strong.

Author Response

Please see the attachment.

Author Response File: Author Response.pdf

Round 2

Reviewer 1 Report

The paper has been revised according to the suggestions provided by reviewers, and it is much improved. The in-depth analysis, clarifications and critical considerations made make this contribution suitable for publication. However, a further (minor) correction is asked.

 

Minor Comment 1

There is some grammar mistake in line 128, 159, 242, 257, 307, 384, 484.

 

Minor Comment 2

Some numerical automatisms don't work in line 460, 476, 484, 492, 513, 528, 533, 540, 543, 644, 651, 657.

Author Response

Thank you for your positive feedback. We made the minor spelling corrections suggested