Dynamic Minimum Service Level of Demand–Responsive Transit: A Prospect Theory Approach
Round 1
Reviewer 1 Report
Comments and Suggestions for AuthorsThe paper presents a comprehensive analysis of DRT service preferences, highlighting the importance of tailored policies based on factors such as primary transportation mode, travel purpose, and age group. This user-oriented perspective enhances the understanding of service expectations and provides practical recommendations for optimizing DRT operations.
By applying behavioral economics principles and quantitative modeling, the study successfully identifies key factors influencing DRT adoption and user satisfaction. The findings contribute to the development of more effective and region-specific policies aimed at improving public transportation accessibility and efficiency.
The literature review is adequate to the authors’ research.
However, I have the fallowing observation:
- While the study presents a new framework, it does not compare its findings with existing DRT service models or policy frameworks in other regions. A comparative analysis could help validate the proposed approach and highlight its advantages or limitations relative to alternative methodologies.
The study moves beyond traditional supplier-centric methods by incorporating user psychology and behavioural economics (prospect theory), offering a more realistic understanding of user preferences in demand-responsive transit (DRT).
Author Response
1. Summary
Dear reviewer, thanks very much for the feedback on this manuscript; we highly value the insightful comments you have written for improving the quality of this paper. Below is our response to your comments and/or the changes we have made in manuscript.
2. Point-by-point response to Comments and Suggestions for Authors
Comments 1: While the study presents a new framework, it does not compare its findings with existing DRT service models or policy frameworks in other regions. A comparative analysis could help validate the proposed approach and highlight its advantages or limitations relative to alternative methodologies.
Response 1: In this study, we additionally reviewed existing DRT service models and policy frameworks and conducted a comparative analysis with frameworks such as those proposed by the Transportation Research Board (TRB) in the United States. Through this comparison, we explained how the minimum service levels (fare, travel time, waiting time, etc.) derived from this study differ from existing DRT operational models and discussed the possibility that these differences stem from regional and policy-related factors.
The revised content has been added to the sixth paragraph of the Introduction, further clarifying the methodological distinctiveness and practical implications of this study. Once again, we sincerely appreciate your valuable feedback.
Reviewer 2 Report
Comments and Suggestions for AuthorsThe authors in this article have made a significant contribution to the analysis of Demand-responsive transit (DRT) which provides flexible, user-centric services. Unlike traditional transit systems, DRT does not operate on fixed routes or schedules but dynamically adjusts routes and stops based on user requests.
Conventional methods for determining the minimum service level of public transportation do not fully account for the unique characteristics of DRT. These approaches are primarily supplier-centric and fail to adequately consider user psychology and travel behavior. To address this, this study applies prospect theory from behavioral economics and uses logistic regression analysis of stated preference survey data to determine minimum service levels based on user perceptions.
The authors used prospect theory in their research. Tversky and Kahneman found that people are about 2.25 times more affected by losses than by gains.
To estimate the minimum service level of DRT and analyze user loss aversion and sensitivity, this study employed a two-step analysis. First, an SP survey was conducted to assess the importance of various DRT service attributes and user acceptance of service changes. Based on this data, criteria for calculating the minimum service level were reviewed, and a logistic regression analysis was performed to determine the reference point for the minimum service level using prospect theory. Next, based on the findings from the first analysis, a second SP survey was designed to estimate the value function parameters of prospect theory using the MLE method. Finally, the general minimum service level, loss aversion, and sensitivity were estimated for the entire sample. A comparative analysis was then conducted to examine variations in the minimum service level, loss aversion, and sensitivity across different user groups based on their primary transportation mode, travel purpose, and age.
This study was conducted based on a survey that was distributed to 600 respondents. After removing irrational or contradictory responses, data from 504 participants were used for analysis.
The authors presented the results of user sensitivity to trivel costs, time spent in the vehicle, and time spent outside the vehicle. The results were shown for different user groups, categorized based on the following criteria: main transportation mode, travel purpose, and user age. In total, the results were presented for 13 groups.
Notes:
Page 4: Line 166
In Chapter 2.2, the abbreviation SP is mentioned for the first time, but its meaning is not explained. Does SP Survey stand for Stated Preference Surveys? If so, it should be clarified in parentheses, for example: SP (Stated Preference) Survey.
Page 4: Line 172
In Chapter 2.2, the abbreviation MLE is mentioned for the first time, but its meaning is not explained. Does MLE Method stand for Maximum Likelihood Estimation? If so, it should be clarified in parentheses, for example: MLE (Maximum Likelihood Estimation) method.
Page 5: Line 190
The travel cost is given as 1,300 KRW. It would be useful to also provide the price in USD in parentheses. For example, 1,300 KRW (0.89 USD).
Page 5: Line 214
There should be a blank line between the equation and the text above, as well as between the equation and the text below. Since this is an equation, a corresponding equation number should be added on the right, for example: (1).
Page 6: Line 229
The chapter number 2.3 is repeated here. The chapter heading should have the number 2.4 instead.
Page 6: Line 240
There is no blank line below the preceding text for this equation. Additionally, the last line of the preceding text is not properly formatted. The equation is also not numbered. The number (2) should be placed to the right of the equation.
Page 9: Line 310
In this group, it is stated that these are people with higher personal income. It might make sense to add a sentence stating that car drivers have already accepted higher costs in advance, as they have chosen this mode of transportation, and the increase in ticket prices doesn't concern them at all.
Author Response
1. Summary
Dear reviewer, thanks very much for the feedback on this manuscript; we highly value the insightful comments you have written for improving the quality of this paper. Below is our response to your comments and/or the changes we have made in manuscript.
2. Point-by-point response to Comments and Suggestions for Authors
Comments 1: In Chapter 2.2, the abbreviation SP is mentioned for the first time, but its meaning is not explained. Does SP Survey stand for Stated Preference Surveys? If so, it should be clarified in parentheses, for example: SP (Stated Preference) Survey. In Chapter 2.2, the abbreviation MLE is mentioned for the first time, but its meaning is not explained. Does MLE Method stand for Maximum Likelihood Estimation? If so, it should be clarified in parentheses, for example: MLE (Maximum Likelihood Estimation) method.
Response 1: We have provided explicit explanations for abbreviations such as SP (Stated Preference) Survey and MLE (Maximum Likelihood Estimation) when they first appear in the manuscript. Revised in Page 4, Lines 168 & 175.
Comments 2: The travel cost is given as 1,300 KRW. It would be useful to also provide the price in USD in parentheses. For example, 1,300 KRW (0.89 USD).
Response 2: The fare 1,300 KRW has been updated to 1,300 KRW (0.89 USD) to improve clarity for international readers. Revised in Page 5, Line 195.
Comments 3: There should be a blank line between the equation and the text above, as well as between the equation and the text below. Since this is an equation, a corresponding equation number should be added on the right, for example: (1). The chapter number 2.3 is repeated here. The chapter heading should have the number 2.4 instead. There is no blank line below the preceding text for this equation. Additionally, the last line of the preceding text is not properly formatted. The equation is also not numbered. The number (2) should be placed to the right of the equation.
Response 3: We have added appropriate blank spaces, assigned equation numbers ((1), (2)), and corrected the chapter number (2.3 → 2.4) to improve consistency and readability. Revised in Page 6, Lines 220 & 247
Comments 4: In this group, it is stated that these are people with higher personal income. It might make sense to add a sentence stating that car drivers have already accepted higher costs in advance, as they have chosen this mode of transportation, and the increase in ticket prices doesn't concern them at all.
Response 4: A sentence has been added to reflect the characteristics of high-income users: "Car drivers have already accepted higher costs in advance, so an increase in ticket prices does not concern them at all.". Revised in Page 9, Lines 312~ 313.
Reviewer 3 Report
Comments and Suggestions for AuthorsAn extremely interesting scientific article deals with the field of minimum service level assessment for demand-responsive transit (DRT). It focuses on the use of prospect theory. After an introduction and a review of the existing state of methods for assessing minimum service level, the authors describe the prospect theory method in detail. The experiment was conducted in South Korea (no more is known about it) based on two surveys (SP surveys). The survey was used to determine the basic criteria for calculating MLS, and the second survey was used to estimate the values ​​of the function parameters in accordance with prospect theory. The results are processed for the entire population and further divided according to the main transportation mode, according to the purpose of travel and depending on the age group. The results are understandable and indicate that the influence of local users can be different in different environments.
The language of the article is understandable and transparent, the article is equipped with an appropriate set of references.
I suggest minor corrections to the authors, namely:
- the scope of the study is not clearly defined in the description of the experiment, I suggest a more precise definition. The authors wrote that there are 504 usable answers - statistical relevance is probably guaranteed - authors' comments on statistical relevance are needed;
- one of the most important segments is determining the impact of travel cost on the user's decision. The starting value is 1300 KRW. I suggest that in addition to the national currency, the value in EURO or USD be written, for greater transparency and easier understanding for readers;
- the formulas used are not numbered (see instructions to authors), and especially the formula in section 2.3 is considered to be more difficult to read. I suggest reformulating it.
Author Response
1. Summary
Dear reviewer, thanks very much for the feedback on this manuscript; we highly value the insightful comments you have written for improving the quality of this paper. Below is our response to your comments and/or the changes we have made in manuscript.
2. Point-by-point response to Comments and Suggestions for Authors
Comments 1: The scope of the study is not clearly defined in the description of the experiment, I suggest a more precise definition.
Response 1: We acknowledge that the description of the study scope could be made more precise. To address this, we have revised the manuscript to explicitly define the scope of our study, including the research objectives, target population, and data collection methods. Revised in Page 5, Lines 185~190.
Comments 2: The authors wrote that there are 504 usable answers - statistical relevance is probably guaranteed - authors' comments on statistical relevance are needed
Response 2: We confirm that the sample size of 504 responses is statistically adequate for analysis. To ensure statistical validity, we have reviewed the sample size based on established statistical guidelines. As a result, the following statement has been added to the manuscript. Revised in Page 5, Lines 189~190.
Comments 3: one of the most important segments is determining the impact of travel cost on the user's decision. The starting value is 1300 KRW. I suggest that in addition to the national currency, the value in EURO or USD be written, for greater transparency and easier understanding for readers
Response 3: The fare 1,300 KRW has been updated to 1,300 KRW (0.89 USD) to improve clarity for international readers. Revised in Page 5, Line 195.
Comments 4: The formulas used are not numbered (see instructions to authors), and especially the formula in section 2.3 is considered to be more difficult to read. I suggest reformulating it.
Response 4: We have added appropriate blank spaces, assigned equation numbers ((1), (2)), and corrected the chapter number (2.3 → 2.4) to improve consistency and readability. Revised in Page 6, Lines 220 & 247
Reviewer 4 Report
Comments and Suggestions for AuthorsWith the use of prospect theory, the authors have tried to find out the users perspectives on the DRT with a comparison to various modes of transportation. The manuscript has been written well with proper arguments against different modes of operations and age, travel purpose, and service levels. On the other hand, I was curious as to why the authors did not include the limitations of the SP survey that they used as a foundation. In addition to this, it is incorporated into the manuscript an additional flavour that is centred on what users are anticipating. I am referring to the type of DRT that they would like to have as a regular part of their lives.
Author Response
1. Summary
Dear reviewer, thanks very much for the feedback on this manuscript; we highly value the insightful comments you have written for improving the quality of this paper. Below is our response to your comments and/or the changes we have made in manuscript.
2. Point-by-point response to Comments and Suggestions for Authors
Comments 1: I was curious as to why the authors did not include the limitations of the SP survey that they used as a foundation.
Response 1: We acknowledge that stated preference (SP) surveys have certain limitations, such as the hypothetical nature of scenarios, potential hypothetical bias, and respondents' difficulty in accurately predicting their real-world behavior. However, SP surveys remain a valuable method as they effectively capture users' psychological tendencies and decision-making processes in controlled scenarios. To address potential limitations, we have added a discussion on the limitations of the SP survey in the manuscript. Revised in Page 4 Lines 169~173.
Comments 2: it is incorporated into the manuscript an additional flavour that is centred on what users are anticipating. I am referring to the type of DRT that they would like to have as a regular part of their lives.
Response 2: We have incorporated a discussion in the manuscript regarding users’ expectations for DRT as a regular mode of transportation. Specifically, we have highlighted that users anticipate a DRT service where, despite a higher fare compared to conventional public transport, in-vehicle time and off-vehicle time are significantly reduced. Revised in Page 13, Lines 421~424.
