Investigating the Effects of Automated Vehicles on Large Urban Road Networks: Some Evidence from Rome

Round 1

Reviewer 1 Report

This paper applies computationally fast models and methods to support the assessment of effects of the AVs introduction on large and real urban networks, it is valuable to the decision-makers of transport policies.

Since the demand-supply interaction model and the cost function parameters are all referred to current literatures, the authors should highlight the contribution and innovation of this paper better in the Conclusion.

What’s more, the applicable of this research to other cities, or other scale of areas shall be discussed.

Author Response

Author's Reply to the Review Report (Reviewer 1)

This paper applies computationally fast models and methods to support the assessment of effects of the AVs introduction on large and real urban networks, it is valuable to the decision-makers of transport policies.

Since the demand-supply interaction model and the cost function parameters are all referred to current literatures, the authors should highlight the contribution and innovation of this paper better in the Conclusion.

What’s more, the applicable of this research to other cities, or other scale of areas shall be discussed.

Reviewer 1:

Since the demand-supply interaction model and the cost function parameters are all referred to current literatures, the authors should highlight the contribution and innovation of this paper better in the Conclusion.

What’s more, the applicable of this research to other cities, or other scale of areas shall be discussed.

Authors:

In order to better highlight the contribution and innovation of this paper, Conclusion has been integrated as follows:

“This application represents the main contribution of this work because it addresses the complexity of simulating the effects of AVs on full-size urban road networks and establishes a promising basis for the successful transferability of this research to other cities, or to other areas on a different scale.”

Reviewer 2 Report

The reviewed paper considers a possibility to apply computationally models to support the assessment of effects of the automated vahicles introduction on large urban networks. The advantage of the work is that the proposed solution was analysed for the complex real-size road network of Rome. The effects of simulations are promising and show the increasing benefits of the introduction of automated vehicles (less total travelled time, higher average network speed, lower average link saturation rate).

The manuscript looks good. It is better to identify the main difference between the studied problem and the existing works. 

The paper is clear and well-constructed, complement prior literature reviews. 

The literature is up-to-date and relevant to the analyzed problem. 

Conclusions are clear presented. The research gap and future research directions are proposed.

Author Response

Author's Reply to the Review Report (Reviewer 2)

The reviewed paper considers a possibility to apply computationally models to support the assessment of effects of the automated vahicles introduction on large urban networks. The advantage of the work is that the proposed solution was analysed for the complex real-size road network of Rome. The effects of simulations are promising and show the increasing benefits of the introduction of automated vehicles (less total travelled time, higher average network speed, lower average link saturation rate).

The manuscript looks good. It is better to identify the main difference between the studied problem and the existing works. 

The paper is clear and well-constructed, complement prior literature reviews. 

The literature is up-to-date and relevant to the analyzed problem. 

Conclusions are clear presented. The research gap and future research directions are proposed.

Reviewer 2:

The manuscript looks good. It is better to identify the main difference between the studied problem and the existing works. 

Authors:

In order to better highlight the contribution and innovation of this paper, Conclusion has been integrated as follows:

“This application represents the main contribution of this work because it addresses the complexity of simulating the effects of AVs on full-size urban road networks and establishes a promising basis for the successful transferability of this research to other cities, or to other areas on a different scale.”

Reviewer 3 Report

Comments:

Descriptions in Figures 1,2, 5 are illegible and need improvement.

In my opinion, you cannot in a literature review, start a sentence with, for example: "[19] investigate the...". If we treat [19] as a literature item then it should be "investigates". It is better to write:  "Item [19] presents research...." because there may be several authors.

Why was the VISUM program used? There are others currently available, such as Aimsun.

In fact, the success of AVs implementation will also be determined by mixed traffic issues. Network Performance Indicators show favorable values for AVs deployment, but CV human factor issues cannot be taken into account in this kind of modeling. This is worth mentioning.

Author Response

Author's Reply to the Review Report (Reviewer 3)

Descriptions in Figures 1,2, 5 are illegible and need improvement.

In my opinion, you cannot in a literature review, start a sentence with, for example: "[19] investigate the...". If we treat [19] as a literature item then it should be "investigates". It is better to write:  "Item [19] presents research...." because there may be several authors.

Why was the VISUM program used? There are others currently available, such as Aimsun.

In fact, the success of AVs implementation will also be determined by mixed traffic issues. Network Performance Indicators show favorable values for AVs deployment, but CV human factor issues cannot be taken into account in this kind of modeling. This is worth mentioning.

Reviewer 2:

Descriptions in Figures 1,2, 5 are illegible and need improvement.

Authors:

Figures 1,2, 5 were improved according to your recommendations.

Reviewer 2:

In my opinion, you cannot in a literature review, start a sentence with, for example: "[19] investigate the...". If we treat [19] as a literature item then it should be "investigates". It is better to write:  "Item [19] presents research...." because there may be several authors.

Authors:

Noted and changes within the paper were made accordingly

Reviewer 2:

Why was the VISUM program used? There are others currently available, such as Aimsun.

Authors:

Visum was used because the initial model was available in this program. Of course, you can use any program (e.g., Aimsun, Emme, and so on) that allows you to use a multiclass equilibrium assignment and enables you to write specific custom code for the proposed changes.

In order to better clarify this point, the text of section 4 (results) after table 1 was integrated as  follows:

“Of course, the reader can use any transport simulation software (e.g., Aimsun, Emme, and so on) that allows to implement a multiclass equilibrium assignment and enables to write specific custom code for the proposed changes.”

Reviewer 2:

In fact, the success of AVs implementation will also be determined by mixed traffic issues. Network Performance Indicators show favorable values for AVs deployment, but CV human factor issues cannot be taken into account in this kind of modeling. This is worth mentioning.

Authors:

In authors’ opinion CV human factor issues, as all other approximations underlying the used class of simulation model, are part of the random terms included in the utility functions (e.g. route choice) of the used random utility models within assignment.

However, to answer your observation and improve the quality of the paper, conclusions was integrated as follows:

“It is worth noting that approximations of such favorable values could be affected by CV human factor issues that the class of models used here does not explicitly allow for, alt-hough they are implicitly considered along with the other approximation effects of a complex system such as road traffic in the random residual of the random utility mod-els used in route choice.”