Examining Factors Influencing the Use of Shared Electric Scooters
Round 1
Reviewer 1 Report
The paper aims to examine the motivations and barriers regarding the use of e-scooters. The paper analyses data from a survey conducted online in spring 2020 taking the campus of the National University of Singapore’s University Town as a case study. Typical users and the different types of transportation available to travel a section of the campus are profiled. The logit regression models are well explained.
The research questions are current and are widely answered in the paper's discussion. The literature research is good, covering issues related to safety in the use of PMDs and the methodology used for analysis, although some important reviews are neglected. The results of the article show the differences in the use of different models. In addition, the limitations of the article are well discussed, and some future research is suggested.
Here below some major and minor suggestions to improve the quality and effectiveness of the paper:
Major comment 1
I have not gotten a clear idea of what the contributions of this paper are. The contributions and differences with existing literature should be emphasized better. For instance, what do the authors propose to differentiate their work from the current literature? I do not find the answer to these questions in the whole manuscript, or the answers are not clear.
Major comment 2
I suggest summarising the research gaps to clarify better how and why your paper advance the research and (possible) practice. Specifically, at the end of the literature, the authors should emphasize the gaps w.r.t the literature this paper aims to address. Something is reported, but it seems to me it is focused on safety only.
Major comment 3
Section 1 shows a review of the literature on different aspects of the use of e-scooters. Line 95 claims that "the literature on e-scooters is still limited," but your study neglects two recent literature reviews. Below are the references; we recommend incorporating them into the analysis and revising the related sentences accordingly.
· https://doi.org/10.3390/su13073692
· https://doi.org/10.3390/su12229505
Major comment 4
Surveys could be carried out using different methods (e.g., Face-To-Face, at home, etc.). The authors should motivate the reasons for using an online survey that have different disadvantages.
Major comment 5
How the variables of your models have been selected? For instance, the authors are suggested to look at the following paper where many variables regarding e-scooter have been considered. See https://doi.org/10.3390/su13169226.
Major comment 6
Provide other statistics to evaluate the model. For instance, provide the global significance, and other statistics that clearly show how your model fits data well. Moreover, in table 4, it is unclear if the coefficients are significant or not. You adopt * for variables having a p-value< 0.1 but nothing is said for other remaining variables. Usually, the significance of the coefficients should be reported including variables significance at 0.001; 0.05, and 0.1. Please clarify.
Major comment 7
Section 5, line 482, suggests future work with different case studies and adding other potential variables in choosing the use of e-scooters. In this regard, it is suggested to consider the level of sustainability in using these vehicles.
Minor Comment 1
Table 4, section 3, is not cited in the text.
Author Response
Please see the attachment.
Author Response File: 
Author Response.pdf
Reviewer 2 Report
The manuscript investigates the motivations and barriers to using e-scooters using stated preference survey data from Singapore university staff and students. In my view, the manuscript would merit favorable consideration following revisions based on the below comments:
1/ On page 3, line 17, it says “Other solutions should be explored and considered instead.” The authors are urged to briefly describe these alternative types of solutions.
2/ On page 7, the authors are encouraged to provide extensive justifications for why the utility form differs depending on the choice. On that note, the authors are encouraged to ground the choice-dependent specific utility specification in the literature. Such a formulation, in my opinion, seems misconstrued.
3/ Given that the respondent-specific variables are incorporated into the MNL formulation, it is reasonable to assume that their corresponding coefficients will vary across the various multinomial options. Nonetheless, they do not. In the same vein as the previous comment, I find something to be amiss here as well.
4/ Along the lines of the two previous comments, I believe that a conditional logit model involving the interaction of respondent-specific attributes and choice-specific attributes need to have been implemented. For information on how to incorporate choice-specific attributes together with respondent-specific attributes, please refer to literature including but not limited to: https://doi.org/10.1016/j.jclepro.2021.126328; https://doi.org/10.1016/j.trd.2011.11.005.
5/ The authors are recommended to make their findings representative to either the Singapore population or the NUS population by considering weights to scale their sample. For information on how to approach it, please refer to: https://doi.org/10.1016/j.tbs.2020.04.002; https://escholarship.org/content/qt82w2z91j/qt82w2z91j.pdf.
Author Response
Please see the attachment.
Author Response File: Author Response.pdf
Reviewer 3 Report
In this research, the authors have explored the factors which affect the use of shared Electric Scooters in Singapore. The research is interesting, However, I have following comments;
1. In abstract, the comparision of the three logit models should be added and some statistical values should be reported.
2. In introduction, it is very long and should be divided into sub-sections to improve the flow of the manuscript.
3. In methods, what is the motivate to do this research study in the University only? Why they did not used any theory such as TPB or NAM? like; Travelers’ Adoption Behavior towards Electric Vehicles in Lahore, Pakistan: An Extension of Norm Activation Model (NAM) Theory.
4. In the discussion, they should include the potential hazards of the speeding behavior of the drivers, I recommend to include following works;
a) Analysis of electric scooter user kinematics after a crash against SUV
b) Injury rates per mile of travel for electric scooters versus motor vehicles
c) Extracting Travelers’ Preferences toward Electric Vehicles Using the Theory of Planned Behavior in Lahore, Pakistan
5. Conclusions should be concise and future research directions and limitations should be clearly mentioned.
Author Response
Please see the attachment.
Author Response File: Author Response.pdf
Round 2
Reviewer 1 Report
The authors addressed my comments. Therefore, the paper is acceptable.
Author Response
Dear Sustainability Editors and Reviewers,
Thank you for reviewing our manuscript titled “Examining Factors Influencing the Use of Shared Electric Scooters”. In addressing the reviewers’ comments, we have revised the paper, and we believe that it has greatly improved and strengthened the work. We truly appreciate your time and invaluable feedback.
___________________________________________________________________________
The authors addressed my comments. Therefore, the paper is acceptable.
Reviewer 2 Report
The majority of my previous round comments have not been adequately addressed. Pending adequate revisions recommended below, I'm afraid I can't recommend the manuscript for favorable consideration.
More specifically, in my view, incorporating respondent specific variables directly in the mode choice utility is misplaced. Along those lines, I did not find any grounding of the chosen utility functional form in solid published literature. The authors are recommended to consider the literature on how to incorporate respondent-specific variables within a choice model, including but not limited to:
https://doi.org/10.1016/j.jclepro.2021.126328; https://doi.org/10.1016/j.trd.2011.11.005.
Regarding the recommendation to add weights, the authors response states - "However, to our knowledge, it is still to some extent debatable whether or not weighting is needed in regression modelling." It is not clear to me what is the literature basis of such a statement. Regardless, the authors further state - "In our case, apart from the expected gender ratio of 1:1, we do not have access to the socio-demographic profile of the full population of staff and students in the U-Town campus to compare and correct the sample. This is because of the presence of several other institutions and retail shops in the area, whose employeesmay have participated in the sample." In such a case, the authors are recommended to use the socio-demographic distribution of University town campus to make the sample representative.
If the authors are unable to find that data either, at the absolute bare minimum, the authors are recommended to add a detailed discussion in the caveats section on how the authors could have corrected the sample by including weights by considering literature, including but not limited to: https://doi.org/10.1016/j.tbs.2020.04.002;
https://escholarship.org/content/qt82w2z91j/qt82w2z91j.pdf
Author Response
Please see the attachment
Author Response File: Author Response.pdf
Reviewer 3 Report
Accepted in current form.
Author Response
Dear Sustainability Editors and Reviewers,
Thank you for reviewing our manuscript titled “Examining Factors Influencing the Use of Shared Electric Scooters”. In addressing the reviewers’ comments, we have revised the paper, and we believe that it has greatly improved and strengthened the work. We truly appreciate your time and invaluable feedback.
___________________________________________________________________________
Accepted in current form.
Round 3
Reviewer 2 Report
Accept
