To What Extent May Transit Stop Spacing Be Increased before Driving Away Riders? Referring to Evidence of the 2017 NHTS in the United States

Round 1

Reviewer 1 Report

This research explores acceptable stop spacing for 15
three kinds of transit service from the perspective of travel behavior. Following comments are made to improve the quality of paper. 

1. The introduction section is too long. It is advised to shorten this section and a separate section on Literature review may be included to enhance the organization of the paper.
2. The Figures number is incorrect as Figure 4 is missing. The citation of Figures is also not in proper order. 
3. Authors provided a little comparison of results. it is suggested to improve this part of the results. 
4. More discussion on results need to be added to strengthen the findings and their policy implications. 

Author Response

We appreciate your efforts to review this paper and your kind review.

Author Response File: Author Response.pdf

Reviewer 2 Report

This manuscript is generally well structured and written, with few grammar and format errors. The research objective is valid. The methodology, data, and analysis all seem to be sound. Findings are supported by the results from the analysis. It may be considered for publication after the following comments are addressed.

1. References to some figures or tables are erroneous and need to be corrected.
2. Some figure numbers and table numbers are also wrong.
3. Please define S_0 and V in Equation (1).
4. In lines 279-280, more details need to be given to justify the logarithm transformation of predictors. It the logarithm transformation necessary? What distributions do they follow after the logarithm transformation?
5. In line 198, I suggest revising it to “The larger value between the walk access time and the walk egress time” to make it clear for the definition of the primary walk time.
6. The conclusion section can be simplified to emphasize major findings, limitations and future research. Discussion part can be moved to Section 4.4.

Author Response

Thanks for your supportive review and insights to enhance the research. We have tried our best to respond to your questions and constructive suggestions as given below.

Author Response File: Author Response.pdf

Reviewer 3 Report

The research employs 2017 US NHTS to explore acceptable transit stop spacing based on passengers’ actual walk time. A stochastic frontier model is developed to infer passengers’ vertex in walk time against inefficiency variance. Results are well analyzed. A few comments are as following. 
1. Factors on transit stop spacing are suggested to be included into the literature review, which may be borrowed in the research and to provide more support for the variable selection.
2. Accessibility is always important for transit. Demand-responsive transit service is also an option. Please refer to the paper: Joint optimisation of regular and demand-responsive transit services.
3. Model validation. Likelihood ratio is presented to show that the model is statistically significant, and the coefficients of frontier and inefficiency variance are explained, but is model test necessary? If not, please give the reason. 
4. Figure 9 shows an interesting finding that the three kinds of transit service are faced with a similar gap between primary and vertex of walk time. Please explain the phenomenon.

Author Response

Thanks for your patient and kind comments on the paper. We have spared no efforts to address the problems you raised. Each review is listed below followed by our response. Thanks for your insights again.

Author Response File: Author Response.pdf