Small Autonomous Vehicles in Pedestrian Contexts: A First Analysis of Logistics Performances in Terms of Commercial Speed

Round 1

Reviewer 1 Report

Comments and Suggestions for Authors

The study is interesting and well-written. It specifically focuses on small ground autonomous vehicles operating in pedestrian environments, which is a relatively new and under-researched area. The research is based on empirical data collected from a challenging pilot project conducted in a real urban environment, providing insights that are not commonly found in theoretical or simulated studies. Some minor comments:

1. How are the data and research results applied to real vehicle route planning? This potential application can be discussed.

2. There are not obvious relationships between the factors in Fig. 4 and Fig. 6.  

Author Response

The study is interesting and well-written. It specifically focuses on small ground autonomous vehicles operating in pedestrian environments, which is a relatively new and under-researched area. The research is based on empirical data collected from a challenging pilot project conducted in a real urban environment, providing insights that are not commonly found in theoretical or simulated studies.

We would like to thank the reviewer very much for appreciating our work and making very valuable observations for the improvement of the article.

We hope you will find the new version of the manuscript, greatly improved following your and the other reviewers' suggestions, better.

 

Some minor comments:

1. How are the data and research results applied to real vehicle route planning? This potential application can be discussed.

Thank you for your comment. These explanations were included in the text of the manuscript:

The statistical analysis of the data made it possible to highlight that no peak periods emerged where droid speed was limited due to the intensity of interactions with pedestrians. This result is probably related to the fact that stability of service operation was not achieved. Had the period of experimentation been extended, it would probably have been possible to identify peak and soft periods and the relative commercial speeds of the Yape. The identification of peak periods would be important for logistics service planning and optimization, considering that sGAVs must slow down or completely stop in presence of objects, such as pedestrians. Operating in off-peak periods or addressing a routing problem to avoid the most congested roads at a given time, would lead both to improved logistical operational performance (reduced delivery times) but also to a reduction in the size of droid fleets required to meet a given delivery demand. Research is moving in this direction: for instance, Bakach et al. [9] explore the effect on deliveries of sGAV travel times, depending on the pedestrian density of the different areas crossed.

 

2. There are not obvious relationships between the factors in Fig. 4 and Fig. 6.  

Thank you for your comment. These explanations were included in the text of the manuscript:

In Figure 4, the x-axis refers to the time from 19 January to 23 February 2023 and the y-axis shows the commercial speeds of all collection trips made during the month of experimentation. Figure 6 instead shows the daily time [hh:mm:ss] on the x-axis and the commercial speed [m/s] on the y-axis.

So in figure 6, the speeds of two collection trips made at 9am but one on 19 January and the other on 20 February have the same value on the x-axis whilst in figure 4 they have different values on the x-axis.

 

Author Response File: Author Response.pdf

Reviewer 2 Report

Comments and Suggestions for Authors

This work is fill the current gap of the availability of reliable data that can be used to develop models to optimize the performance of autonomous vehicles, where the operational performance of the service done by the droids, with particular attention to the interactions between droids and pedestrians and the ability of users to load and unload droids are analyzed. I have following concerns in the paper before further proceedings;

 

The papers reviewed for the literature survey are mostly older than 2020. Please update the section considering latest existing works.

The keywords are not arranged alphabetically.

Why you applied the 5MA technique as other better options are available?

Figures are not explained in the text especially the Fig. 8.

The obtained results are not compared with the existing works for validation. Please justify.

Author Response

This work is fill the current gap of the availability of reliable data that can be used to develop models to optimize the performance of autonomous vehicles, where the operational performance of the service done by the droids, with particular attention to the interactions between droids and pedestrians and the ability of users to load and unload droids are analyzed. I have following concerns in the paper before further proceedings;

 We would like to thank the reviewer very much for appreciating our work and making very valuable observations for the improvement of the article.

We hope you will find the new version of the manuscript, greatly improved following your and the other reviewers' suggestions, better.

 

The papers reviewed for the literature survey are mostly older than 2020. Please update the section considering latest existing works. 

The body of knowledge was re-analysed and more useful works were found to be cited. 13 new works were cited and now, of the 40 articles cited, 18 were published from 2020 to 2024. In particular, 2 recent valuable papers were found that were very relevant to the research:

• Kocsis, M., Zöllner, R., Mogan, G. 2022. Interactive System for Package Delivery in Pedestrian Areas Using a Self-Developed Fleet of Autonomous Vehicles. Electronics, 11, 748. https://doi.org/10.3390/electronics11050748
• Bakach I., Campbell A.M., Ehmke J. F. 2021. Robot-Based Last-Mile Deliveries With Pedestrian Zones Front. Future Transp., 04 January 2022 Sec. Freight Transport and Logistics Volume 2 | https://doi.org/10.3389/ffutr.2021.773240

Thank You!

The keywords are not arranged alphabetically. 

Done. Thank You!

Why you applied the 5MA technique as other better options are available?

Done. Thank You! In the first paragraph of the section 3.3

Figures are not explained in the text especially the Fig. 8. 

Done. Thank You!

The obtained results are not compared with the existing works for validation. Please justify. 

Done. Thank You!

It is difficult to compare the results because first, there are few field trials where droids are used for long periods in public pedestrian areas. Secondly, the Yape used in this research is smaller in size than the vehicles used in similar research, for example in Kocsis, M., Zöllner, R., Mogan, G. 2022. This was explained in lines 136-144

Regarding the adaptation curve of humans to droids, lines 556 to 580 compare with existing work and highline practical implications.

Regarding peak periods, from line 581 to 610 it is compared with existing work and highlined practical implications.

Author Response File: Author Response.pdf

Reviewer 3 Report

Comments and Suggestions for Authors

In this study, the performance of small autonomous vehicles on a specific route for commercial purposes over different senarios is analyzed. The study is generally well-designed and has a logical flow. It can be re-evaluated after some corrections. My suggestions are as follows:

1) A little more information about the results should be presented in the abstract.

2) Past studies should be analysed in detail and the necessity of the proposed method should be demonstrated. More current studies should be analysed.

3) The study area should include coordinates and legend information in accordance with the map representation, which will increase the comprehensibility.

4) The technical features of the device used should be mentioned and its suitability for the study should be evaluated.

5) Are the selected cases sufficient for the analysis? Can the effectiveness of the study be increased with more scenarios?

Author Response

In this study, the performance of small autonomous vehicles on a specific route for commercial purposes over different senarios is analyzed. The study is generally well-designed and has a logical flow. It can be re-evaluated after some corrections. My suggestions are as follows:

We would like to thank the reviewer very much for appreciating our work and making very valuable observations for the improvement of the article.

We hope you will find the new version of the manuscript, greatly improved following your and the other reviewers' suggestions, better.

 

1) A little more information about the results should be presented in the abstract.

Done. Thank You! From line 24 to line 30 approx.

2) Past studies should be analysed in detail and the necessity of the proposed method should be demonstrated. More current studies should be analysed.

The body of knowledge was re-analysed and more useful works were found to be cited. 13 new works were cited and now, of the 40 articles cited, 18 were published from 2020 to 2024. In particular, 2 recent valuable papers were found that were very relevant to the research:

• Kocsis, M., Zöllner, R., Mogan, G. 2022. Interactive System for Package Delivery in Pedestrian Areas Using a Self-Developed Fleet of Autonomous Vehicles. Electronics, 11, 748. https://doi.org/10.3390/electronics11050748
• Bakach I., Campbell A.M., Ehmke J. F. 2021. Robot-Based Last-Mile Deliveries With Pedestrian Zones Front. Future Transp., 04 January 2022 Sec. Freight Transport and Logistics Volume 2 | https://doi.org/10.3389/ffutr.2021.773240

The necessity of the proposed research is explained, for example, from line 126 to line 144 approx.

 Thank You!

 

3) The study area should include coordinates and legend information in accordance with the map representation, which will increase the comprehensibility.

Done. Thank You!

4) The technical features of the device used should be mentioned and its suitability for the study should be evaluated.

The description of the device used and the technical features of the sGAV were introduced in section 2.1

Thank You!

 

5) Are the selected cases sufficient for the analysis? Can the effectiveness of the study be increased with more scenarios?

It would have been very useful to continue the experiment until a stable operation of the logistics service was achieved. This was not possible due to the long time required for the implementation of the service and therefore the following time constraints. However, the results obtained we think may be important for future developments. For example, the adaptation curve that resulted from analysis of the experimental data suggests that training both the population and the users of the logistics service who will have to interact with the droids is crucial. The human-machine interface is again a critical aspect.

Thank You!

Author Response File: Author Response.pdf

Reviewer 4 Report

Comments and Suggestions for Authors

The manuscript proposes an interesting case study research on the use of droids for the delivery of goods. In particular, the Authors evaluated the operational performances of the service done by the droids focusing on the interactions between droids and pedestrians, as well as on the ability of users to load and unload droids.

However, before considering it for publication, several improvements are needed.

First, the Authors should better explain how the current study can match with the journal’s topics.

Then, research motivations have to be elaborated more. Indeed, the research gap the Authors want to deal with has to be discussed in detail considering extant studies. The research questions raised in section 3 are not justified in a scientifically sound manner.

Hence, in this reviewer’s opinion, the introduction section should be re-organized in order to:

·       explain the link with journal topics;

·       highlight the research questions/motivations, i.e. the research gap to deal with;

·       describe how you intend to address the underlined research gap.

In the materials and methods section, the research approach should be introduced at a general level: i.e., the proposed procedure and the tools used should be introduced with sufficient detail to allow others to replicate.

The discussion of results also needs to be elaborated more: the Authors should discuss the results and how they can be interpreted also considering extant studies. In particular, research findings and practical implications have to be pointed out.

Moreover, data provided in tables are not formatted using international notations (e.g. decimals should be indicated using a full stop symbol).

In summary, although the case study description appears to be very interesting, the manuscript lacks a scientifically sound background and structure. Hence,  in this reviewer’s opinion, the manuscript should be rejected, inviting the Authors to re-submit it once the above criticalities are solved.

Comments on the Quality of English Language

English language is fine, but scientific notations have to be updated following the journal rules.

Author Response

The manuscript proposes an interesting case study research on the use of droids for the delivery of goods. In particular, the Authors evaluated the operational performances of the service done by the droids focusing on the interactions between droids and pedestrians, as well as on the ability of users to load and unload droids. 

We would like to thank the reviewer very much for appreciating our work and making very valuable observations for the improvement of the article

However, before considering it for publication, several improvements are needed.

First, the Authors should better explain how the current study can match with the journal’s topics.

Logistics services operated by sGAVs in pedestrian areas seem to promise greater sustainability. This issue has been explained from line 52 to line 64.

 

Then, research motivations have to be elaborated more. Indeed, the research gap the Authors want to deal with has to be discussed in detail considering extant studies.

Referring to the introduction that has been re-written following your suggestions, research motivations have been introduced from line 126.

…most studies on sGAVs have been theoretical in nature, and there is a clear need for case studies and real implementations on public field, as pointed out by Alverhed et al. [25]. There is a lack of empirical data necessary for the definition of efficient optimization algorithms for logistic services in pedestrian areas that can also be used for training and testing machine learning algorithms. Indeed, these learning-based methods require representative data that do not exist for pedestrian environments [26]. Moreover, it is also important to take into account that logistics systems with different characteristics and operated by different autonomous vehicles must be optimised with data appropriate to the specific system. This makes the need for empirical data specific to different categories of sGAVs even more critical.

research gap the Authors want to deal with, from line 136.

The research presented in this article is similar to that of Kocsis et al. [15], but the autonomous vehicles used for last-mile distribution are very different in size and load capacity. The electric golf car adapted by Kocsis et al. [15] has a length of 240 cm and a width of 119 cm with a maximum load capacity of 360 kg; this research, on the other hand, refers to a small droid, called Yape and produced by the company YAPE [27], which has a length of 70 cm and a width of 70 cm with a maximum load capacity of 10 kg. Due to these differences in the characteristics of sGAVs, the logistical performance, e.g. in terms of travel time and service, and the impact that sGAVs have on pedestrian flows in the area in which they operate, are different..

The aim of the proposed research, from line 151 to line 161

The aim of the proposed statistical analysis is twofold. First, commercial speeds are affected by interactions with humans. Humans are those who interact with sGAVs on the one hand, because they share the same physical space, on the other hand, because they have to collaborate with sGAVs in logistic activities. Therefore, our goal is to understand if there is an adaptation period for humans in both dodging Yapes moving in pedestrian environments and/or in collaborating with Yape during loading and unloading activities. Secondly, since commercial speeds are influenced by interactions with pedestrian flows and pedestrian flows change during the time of the day, we wish to verify whether the Yape’s commercial speeds are correlated with the daily time. Specifically, we verify whether their commercial speeds are higher when pedestrian flows are lower (off-peak periods) and vice-versa (peak periods).

 

The research questions raised in section 3 are not justified in a scientifically sound manner.

You are right, these are not research questions

Hence, in this reviewer’s opinion, the introduction section should be re-organized in order to:

• explain the link with journal topics;
• highlight the research questions/motivations, i.e. the research gap to deal with;
• describe how you intend to address the underlined research gap.

The introduction was completely re-written following your suggestions

In the materials and methods section, the research approach should be introduced at a general level: i.e., the proposed procedure and the tools used should be introduced with sufficient detail to allow others to replicate. 

The description of the tool used and the technical features of the sGAV were introduced in section 2.1

Thank You!

 

The discussion of results also needs to be elaborated more: the Authors should discuss the results and how they can be interpreted also considering extant studies. In particular, research findings and practical implications have to be pointed out.

Done. Thank You!

The body of knowledge was re-analysed and more useful works were found to be cited. 11 new works were cited and now, of the 38 articles cited, 16 were published from 2020 to 2024. In particular, 2 recent valuable papers were found that were very relevant to the research:

• Kocsis, M., Zöllner, R., Mogan, G. 2022. Interactive System for Package Delivery in Pedestrian Areas Using a Self-Developed Fleet of Autonomous Vehicles. Electronics, 11, 748. https://doi.org/10.3390/electronics11050748
• Bakach I., Campbell A.M., Ehmke J. F. 2021. Robot-Based Last-Mile Deliveries With Pedestrian Zones Front. Future Transp., 04 January 2022 Sec. Freight Transport and Logistics Volume 2 | https://doi.org/10.3389/ffutr.2021.773240

It is difficult to compare the results because first, there are few field trials where droids are used for long periods in public pedestrian areas. Secondly, the Yape used in this research is smaller in size than the vehicles used in similar research, for example in Kocsis, M., Zöllner, R., Mogan, G. 2022. This was explained in lines 136-144

Regarding the adaptation curve of humans to droids, lines 556 to 580 compare with existing work and highline practical implications.

Regarding peak periods, lines 581 to 610 compare with existing work and highline practical implications.

 

Moreover, data provided in tables are not formatted using international notations (e.g. decimals should be indicated using a full stop symbol).

Done. Thank You!

 

In summary, although the case study description appears to be very interesting, the manuscript lacks a scientifically sound background and structure. Hence,  in this reviewer’s opinion, the manuscript should be rejected, inviting the Authors to re-submit it once the above criticalities are solved.

We hope you will find the new version of the manuscript, greatly improved following your and the other reviewers' suggestions, better.

Author Response File: Author Response.pdf

Round 2

Reviewer 3 Report

Comments and Suggestions for Authors

I thank the authors for their responses. The study seems ready in its current state.

Reviewer 4 Report

Comments and Suggestions for Authors

The Authors have satisfactorily improved the quality of the manuscript following the provided suggestions. Hence, in this reviewer's opinion, the manuscript can be considered for publication.