Optimization of Shared Autonomous Vehicles Routing Problem: From the View of Parking

Round 1

Reviewer 1 Report

Review of the article

 “Optimization of shared autonomous vehicles routing problem: from the view of parking”

 

This work is relevant, dedicated to the current problem of minimizing the cost of using shared autonomous vehicles (SAV) in the urban network, taking into account the demand for travel. The novelty of this research lies in the complex approach to solving the problems of vehicle routing and parking. The accuracy of the obtained results emphasizes the practical significance of the work. However, there are some inaccuracies in the text of the article, in accordance with the following comments and recommendations:

1. The formation of separate sets of O and T (initial and final depot respectively) excludes the case where the SAV can return to the initial depot. This case seems more realistic within one city. Was there really such a need for two different sets? And why are the sets O and T missing in Figure 1?

2. Section 3 (line 100) states that SAVs of the same type are used in the network. Indicate please, what type of SAVs was used in this study? It is of interest to compare system indicators when using different models of SAVs, which, first of all, will affect the cost of energy c_e. It can be considered as one of the directions of further research.

3. In section 3, it is better to supplement the description of the sets U, Sq and S. What is the difference between the elements of these sets? It is also not completely clear why the elements of sets B and S are defined as "dummy" (Table 1).

4. The stated measurement units of the c_e parameter (Table 1 and Table 2) are questionable. Based on formula (1), the specified parameter should determine the cost of energy per unit of time, but otherwise stated. Please check.

5. How were the weighting factors we, wc, ws determined (Table 2)? Please add an explanation.

6. From Table 4 it is difficult to understand the difference between PTP and PT. An appropriate explanation should be added.

7.  It is not clear from the text of the article whether the parameter v_t is a constant value or an average value of the speed. On the basis of which statistical data is its numerical value determined? Are real network conditions considered, including the possibility of stopping at intersections, peak hours, acceleration times, etc.?

8. There are some technical errors in the text of the article:

- numbering of subsections in Section 2 (line 46 and line 72);

- in Section 5.2, a reference to the table (line 284 and line 289);

- reference to the figure (section 5.2.2, line 303) and numbering of Figure 17 (d);

- in Figure 17 and in Table 2, the parameter vt (km/h) is indicated, which is not included in the list of parameters in Table 1;

- in formula (1), the sum of all terms must be enclosed in parentheses as a common argument of the  function min;

- the objective function (1) should be denoted by f(x) for consistency with Algorithm 1 and Algorithm 2.

9. I recommend finalizing the conclusions.

 

Author Response

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Reviewer 2 Report

This manuscript addresses the issue of parking decisions and going routes for shared autonomous vehicles and proposes variable neighborhood search (VNS) heuristic solutions with the aim of reducing vacant vehicle kilometers traveled.

Here are a few suggestions for the authors:

1. It is recommended that the literature review be more focused on the research topic of this paper;

2. The paper has many assumptions and premises, and it is suggested to properly depict under what possible application scenarios this study is conducted;

3. There are too many formulas and symbols in this paper, but the elaboration is on the low side, I wonder if it can be optimized;

4. The current conclusion section is mainly a summary, while the conclusion are insufficient, and it is suggested to further deepen the conclusion section;

5. Maintain the consistency and correctness of the reference format.

 

The language is basically smooth and readable, and it would be better if the phrases were improved.

Author Response

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Author Response File: Author Response.docx

Reviewer 3 Report

The ideas in this paper are good. However, this article still need to be revised as follows:

1.     The Introduction and Literatures review also need to be enhanced, especially on routing optimization problem and solution algorithms, and articles in recent years. These articles may be helpful for improving this paper: the fourth-party logistics routing problem using ant colony system-improved grey wolf optimization, 4pl routing problem using hybrid beetle swarm optimization, a hybrid metaheuristic algorithm for the multi-objective location-routing problem in the early post-disaster stage.

2.     Constraint 5 should be to return to base after completing all services?

3.     The meaning expressed by N-P in a constraint.

4.     What is the difference between the arrival and departure time of constraint 13, 14 and15?

5.     At the end of the paper, the experiment of increasing parking fee is done, but the specific fee should be charged which is not given, please explain the significance.

6.     The paper discussed the value of the model and the case, however the optimization aspect has been ignored.

7.     The proposed VNS algorithms need to be analyzed about its parameters setting and abilities. It suggested to compared the VNS with this kind of algorithms, which can be seen in, two-level principal-agent model for schedule risk control of IT outsourcing project based on genetic algorithm, or, a bilevel whale optimization algorithm for risk management scheduling of information technology projects considering outsourcing. Even, it also can be compared with recently designed algorithms like CSOA. References like, credit portfolio management using two-level particle swarm optimization. That is one of the way to verify the contribution of the paper.

Minor editing of English language required

Author Response

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Author Response File: Author Response.docx

Round 2

Reviewer 3 Report

All qeustions have been addressed.

Author Response

Dear reviewer,

Thank you for reviewing our paper. We have revised the manuscript and the main changes are listed as follows:

1. We have added explanations of the number of operators in Section 4.3.

2. It is reasonable that if the time required for a single shake is very small, even if the shaking time limit is set to 0.01s, the actual upper limit number of shaking that can be done is still large. So, we have used the number of shaking operators to test the optimization effect of the algorithm in Section 5.2.1.

3. We have changed the parking fee step from 0.02￥/min to 0.04￥/min in Section 5.2.3. Now it is more concisely and more expressively.