Development and Evaluation of Simulation-Based Low Carbon Mobility Assessment Models

Round 1

Reviewer 1 Report

A very interesting article. I have no comments.

Author Response

We thank Reviewer #1 for their endorsement of the paper in its current form. 

Reviewer 2 Report

Interesting and well-constructed paper. In the reviewed paper, the Authors presented the research that could help decision-makers estimate the carbon footprint of transport networks within their jurisdictions and evaluate the impacts of emission-reduction interventions, through the development of a simulation-based low carbon mobility assessment model. The model was developed based on a framework that integrates multiple mobility components including individual travel preferences, traffic simulation, and an assessment interface to create a seamless tool for the end-user. The feasibility of the assessment model was demonstrated in a case study for a local city council in Melbourne. In one of many scenarios reported in this paper, the model showed that maintaining current levels of emissions would require a 20% reduction in vehicle trips by 2030, and a much larger reduction would be required to reduce the levels of greenhouse gas emissions and achieve desired emissions reductions targets. The paper concludes with recommendations and future directions to extend the model’s capabilities and applications.

Author Response

We thank Reviewer #2 for their thorough review of the paper and comments which demonstrate an excellent understanding of the paper. We also thank Reviewer #2 for their endorsement of the paper in its current form. 

Reviewer 3 Report

This paper presents a simulation-based approach to assess the impacts of low-carbon mobility options (or reduced emission interventions). The approach includes a travel preference survey component, traffic model, and impact models. The approach is demonstrated for a local council in Melbourne. Overall, this is a well-written and interesting paper. Model developments and results are quite well described. I only have several minor comments for consideration.

The literature review is good. However, the section about low carbon mobility policy assessment models could be elaborated. For example, what are the main types of tools for assessment at micro and macro levels?

The model is developed for a confined area such as a local council. While the majority of travel could be well within the council, many trips could originate from the council and end somewhere else (or originate somewhere else, but end within the council). These trips could be substantial (especially if there are main arterials with major through traffic), contributing to emissions in the area. It is unclear if these factors have been accounted for. If not, some discussions on implications to the results should be provided.

Author Response

We thank Reviewer #3 for their thorough review and comments which also demonstrate an excellent understanding of the paper. We provide responses the reviewer’s minor comments next.

Comments: The literature review is good. However, the section about low carbon mobility policy assessment models could be elaborated. For example, what are the main types of tools for assessment at micro and macro levels?

Response: We have expanded on the relevant section (Section 1.3) of the paper and included the different types of policies as outlined below.

Changes to manuscript (starting line 158): Typically these policies target one of three key areas: “Avoid”, “Shift”, “Improve”. The “Avoid”  policies generally work at the macro level and target initiatives to avoid or reduce the need for travel. The “Shift” policies also generally work the macro level and focus on transitioning travel from high energy-intensive modes of transport to lower or more efficient modes (e.g. cycling or public transport).  The  “Improve”  policies are aimed at technological or infrastructure improvements to improve operations and reduce energy consumption, and are thus generally more suited as micro level interventions. More recently a fourth area of policies “Share” has started to emerge. The “Share” policies focus on overcoming barriers to promote a shift to shared modes of travel (e.g. ridesharing or carpooling) and are good strategies for both macro and micro level interventions [25].

Comments: The model is developed for a confined area such as a local council. While the majority of travel could be well within the council, many trips could originate from the council and end somewhere else (or originate somewhere else, but end within the council). These trips could be substantial (especially if there are main arterials with major through traffic), contributing to emissions in the area. It is unclear if these factors have been accounted for. If not, some discussions on implications to the results should be provided.

Response: We have expanded on the relevant sections (Section 2.3 and Section 4.1) of the paper and included responses and clarifications to the issues raised by the reviewer.

Changes to manuscript (Section 2.3, starting line 343): As this tool’s focus is to quantify the mobility impacts at a local council level, and they would need to be developed and adopted by each council, trips that originate or end within a council’s boundaries were included. However, through traffic or trips that continue through the study area were not considered because generally such trips are more likely to use major arterial roads rather than use local streets or roads. Such trips  would also be picked up or included in the relevant local council low carbon mobility models where they originated or ended their travel.

Changes to manuscript (Section 4.1, starting line 524). As outlined before, it is expected that each council would develop and adopt their own low carbon mobility initiatives and models. Therefore, whilst these results measure the impacts of travel within the study area, the impacts of through traffic are not included as these would be picked up by the relevant council low carbon mobility models. There is certainly scope in future research studies to consider how the different low carbon mobility models for adjacent councils can be either integrated or fused to ensure that there are consistent strategies that target through traffic in their areas such as provision of by-pass routes to encourage a shift of through traffic to major arterial roads rather than local council roads.

Round 2

Reviewer 3 Report

The authors have successfully addressed all comments