How Will the Technological Shift in Transportation Impact Cities? A Review of Quantitative Studies on the Impacts of New Transportation Technologies

Round 1

Reviewer 1 Report

The authors reviewed 32 simulation studies of AV use in cities. However, there is no experience of AV deployment in practice so definitive statements about performance cannot be substantiated, for instance ‘Automated vehicles drive more efficiently at higher speeds through smoother driving and a shorter minimum headway, resulting in an increase in capacity.’[line 87]

The lack of real-world experience of AV performance means that the choice of parameters employed in the models must be based on considerable judgement, hence the very diverse and contradictory conclusions of the modelled impacts of AVs.

The paper makes no reference to the likely timing of deployment of AVs, now generally seen as on a longer timescale than enthusiasts earlier had supposed. The discussion of the impact of AVs on emissions would not be relevant if, as seems likely, electric propulsion precedes automation.

The conclusion of the paper that the new technologies could be both beneficial and detrimental is doubtless correct but not illuminating, while the descriptive account of how the various factors play out does not advance understanding.

A problem with travel modelling generally, and of simulation studies of AVs in particular, is the lack of validation by comparison with observed outcomes. A situation where validation by observation may be feasible is in the case of ride-hailing, where information is available about the impact on city traffic and where simulation modelling is carried out by the service providers and, I think, by researchers; but shared non-automated vehicles are not considered in this paper.

I do not think that the diagrams in Appendix C are helpful.

 

 

Author Response

Thank you for giving us the opportunity to submit a revised draft of our manuscript titled ‘How will the technological shift in transportation impact cities? A review of quantitative studies on the impacts of new transportation technologies’ to ‘Sustainability’. We appreciate the reviewers’ valuable feedback and insightful comments on our manuscript. We have been able to incorporate changes to reflect most of the suggestions provided by the reviewers. We have highlighted the changes within the manuscript. Attached is a point-by-point response to the reviewer 1’s comments and concerns.

Author Response File: Author Response.pdf

Reviewer 2 Report

The paper “How will the technological shift in transportation impact cities? A review of quantitative studies on the impacts of new transportation technologies “ covers impact of technological shift in transportation in terms of five aspects: traffic flow, space use, energy consumption, transit and active mobility, and economic affordability through a review of 32 quantitative studies. The authors provide a detail explanation on the review process as well as how to find the drivers and levers that influence impacts. Overall this paper shows an excellent storyline and presents numerous interesting examples to support their opinions. I’d just like to give a couple of suggestion as one of the readers.

Firstly, I’m curious of which standard was utilized when they picked up the journal. The authors could provide the keywords or the name of journal database selected.

Secondly, as a reader, some categorization was kind of confused. For example, it seems to be defined whether the automated vehicle(AV) include private car only or transit as well. Even it should be clear the scope of the “vehicle”, as the range of it would be so expansive in the readers’ mind from micromobility to the massive mobility.  Also, you may want to make sure which levels of automation technology (Level 3, 4 or 5?) was applied to each study.

Finally, it would be more interesting if this study could include the review (or comparison) of the qualitative researches. However, this manuscript is still well-structured review article addressing lots of implications for the next research on the new technologies of transportation – automation, vehicle sharing, electrification, and connected vehicles.

Author Response

Dear Mr Vincent Gan,

Thank you for giving us the opportunity to submit a revised draft of our manuscript titled ‘How will the technological shift in transportation impact cities? A review of quantitative studies on the impacts of new transportation technologies’ to ‘Sustainability’. We appreciate the reviewers’ valuable feedback and insightful comments on our manuscript. We have been able to incorporate changes to reflect most of the suggestions provided by the reviewers. We have highlighted the changes within the manuscript. Attached is a point-by-point response to the reviewer 2’s comments and concerns.

Author Response File: Author Response.docx

Reviewer 3 Report

This is a very well-written paper, clear communication and easy to follow. Thank you. There are a few issues I’d like to raise:

 

1. It’s true that the definition of sustainability is very wide and it’s not possible to assess every aspect of it. However, more literature should be provided on this issue. The arbitrary selection of the 5 aspects of sustainability should be justified in the context of new transportation technologies. I would have expected a justification stating “after a careful review of many quantitative new transportation technologies, these sustainability factors are provided and we select the top 5 because they’re the most relevant/mentioned etc…”
2. The article refers to many types of the new transport technologies such as ride share platforms, but most of the papers seem to be focused on variations of AVs. I think the title of the paper, abstract and some content will need to change because it doesn’t review technologies such as ride share as extensively.
3. Please expand the geographical focus to include China and other countries where the development is rapid and literature is extensive.
4. The Papa and Ferreira approach i.e. studying the isolated vs holistic scenarios – is it suitable for other types of technological shift which are not automated vehicles mentioned in this study?
5. I think there should be some high-level statistics of the number of papers/type of topics from Scopus/Web of Science on these kind of technologies. There is a vast amount of literature. 32 papers seems very low and makes me question what else is out there.

Author Response

Thank you for giving us the opportunity to submit a revised draft of our manuscript titled ‘How will the technological shift in transportation impact cities? A review of quantitative studies on the impacts of new transportation technologies’ to ‘Sustainability’. We appreciate the reviewers’ valuable feedback and insightful comments on our manuscript. We have been able to incorporate changes to reflect most of the suggestions provided by the reviewers. We have highlighted the changes within the manuscript. Attached is a point-by-point response to the reviewer 3’s comments and concerns.

Author Response File: Author Response.pdf

Round 2

Reviewer 1 Report

None