Assessment of Accessibility and Activity Intensity to Identify Future Development Priority TODs in Hefei City
Round 1
Reviewer 1 Report
I have reviewed the manuscript entitled “Assessment of the accessibility and activity intensity to identify future development priority TODs in Hefei city”. The concept of the paper is interesting. However, I just have some comments:
- Abstract
The abstract could use more introductory language which speaks to why this assessment is needed. What exactly is the significance of this issue? It could also describe the methodology used before the results are presented. I would like to hear more about what are the implications of the study towards the end of the abstract.
- Introduction
The introduction could also be structured better, and the literature explained in relation to the aim of this study needs to be clearer. The wording in the literature review cites what was done or the aim of the studies but the result and impact were not always clear. I would like to ask the authors to extend this section by adding some new references.
- Materials and Methods
Why Hefei is selected for this study? Why not other cities?
Research design and methodology are missing. I would like to see the figure for this section. How data is assessed and the method chosen for this study?
From where the authors have collected the multiple data for this research, please provide the website links, etc.
Why use Transit-oriented Development (TOD) for this research, why not others?
- Results
The discussion needs to be clearer and more concise.
Please compare the result with previously published studies, and how your study results are better than the previous one, please elaborate
Figures should be clear in the revised version.
Recommendation: Major revision
Author Response
Point 1: The abstract could use more introductory language which speaks to why this assessment is needed. What exactly is the significance of this issue? It could also describe the methodology used before the results are presented. I would like to hear more about what are the implications of the study towards the end of the abstract.
Response 1: In the revised paper, at 8-11, the research background of Hefei City was introduced, and the necessity of TOD development in Hefei was explained. At 12-13, the shortcomings of current TODs in Hefei, and the reasons why TODs should be given priority in this research were explained. At the same time, at 15-17, we illustrated the methods used in this study. At 17-19, we introduced the final results.
Point 2: The introduction could also be structured better, and the literature explained in relation to the aim of this study needs to be clearer. The wording in the literature review cites what was done or the aim of the studies but the result and impact were not always clear. I would like to ask the authors to extend this section by adding some new references.
Response 2: At the 100-104 of the revised paper, we added the research background, purpose, and results of the cited literature, and also expressed the relationship with our research. At the same time, to explain the importance of investment allocation, we also cited a new paper at 104-108.
Point 3: Why Hefei is selected for this study? Why not other cities?
Response 3: In the revised paper, we added some information to explain the reason for choosing Hefei, at 154-160.
“Many previous studies on TOD in China focused on metropolises, such as Beijing, Shanghai, Shenzhen, etc. However, with the recent promotion, medium-sized cities are increasingly adopting TOD concepts in urban planning. Unlike the mature public transport systems of metropolises, TOD development in these medium-sized cities is still under development. Hefei is one of the medium-sized cities that are developing TODs. This paper chose Hefei city as a case study to find the future development directions of the TOD concept in medium-sized cities.”
Point 4: Research design and methodology are missing. I would like to see the figure for this section. How data is assessed and the method chosen for this study?
Response 4: In Section 2 of the revised paper, we added a research flow chart and a brief introduction to help readers understand the ideas and methods of our research design, which is shown at 127-130.
Point 5: From where the authors have collected the multiple data for this research, please provide the website links, etc.
Response 5: We have added a column in Table 2 to show the source of data, and also marked them in the part 2.2.3 (at 275-278).
Point 6: Why use Transit-oriented Development (TOD) for this research, why not others?
Response 6: In the 2.1 previous research, at 132-140, we added some information to explain the importance of TOD and the reasons for choosing TOD as the research object.
“The important characteristic of the TOD concept is that it the integration of land-use and public transport, to encourage urban development around public transport nodes and improve quality of life. Many researchers find that TOD development has other positive effects on urban development. For example, Dong [37] found that TOD greatly reduced the travel costs of residents by comparing the travel costs between TOD and non-TOD households. Li [38] stated that TOD has a positive impact on house prices, even in China. By investigating TOD's transportation-related carbon dioxide emissions, Ashik [39] proved that TOD can reduce the carbon dioxide emissions of human activities and help achieve sustainable environmental development.”
Point 7: The discussion needs to be clearer and more concise.
Response 7: We have rewritten the discussion part and conducted a more depth analysis of the research results. It is proposed that these priority TODs can be further subdivided according to their different functions. The specific explanation is at 318-413.
Point 8: Please compare the result with previously published studies, and how your study results are better than the previous one, please elaborate.
Response 8: In the discussion, we compared the results and methods of this research with previous studies. At the same time, the advantages of this study are shown at 407-411.
“The current research proposes a simpler method to discover a similar broad group of priority TODs. At the same time, adopting the node-place model to find priority TODs has the advantage of helping to discover weaknesses of TODs and the ability to suggest development strategies, compared to other methods, such as analyzing the relative efficiency of TODs used by Lee [19].”
Point 9: Figures should be clear in the revised version.
Response 9: We have redrawn the figures to make them clearer, such as Figure 4 and Figure 7. At last, thank you very much for your precious comments.
Author Response File: 
Author Response.docx
Reviewer 2 Report
This paper presents an analysis of transit station areas in Hefei, aiming to identify which ones should be given priority for investment and also to assess whether the need is for transportation improvement at each station area (node) or for increased urban development. The station areas have been designated for transit-oriented development (TOD); currently, some are highly developed with diverse land uses and a high level of accessibility while others are less so. The paper uses a simple node-place conceptual model (following Bertolini, 1999) together with a set of indicators to evaluate each station area. The node-place analysis is augmented using the silhouette method for determining the appropriate number of clusters among the station areas; the resulting clusters are deemed to be priority categories for investment.
The node-value of the transit stop describes accessibility of each “TOD”, with the authors considering metro, bus, and auto access. For place-value, the authors considered the area within 500 meters of each station, apparently measuring square meters of six highly aggregated land uses. How this is measured needs clarification because Table 2 indicates it’s the area of land devoted to each land use type whereas the text says, “Some researchers directly calculate the geometric area of each land-use type in the study area to reveal the activity intensity [32]. Therefore, this paper follows the same method to calculate the area of six different land uses for measuring the place-value.” Is it land area or land use area?
In addition, at 156-157 the authors state, “This study selected several indicators to make the node-place model operable. As shown in Table 1 [sic].” Table 1 lists number of residents, number of workers, and degree of functional mix as the indicators for place, whereas Table 2 lists land areas of various types as place indicators along with the functional mix. The authors need to clarify what measures they actually used.
Table 2 lacks clarity in other ways. It appears the authors skipped D4 in the right hand column (got their numbering wrong.) Also, rather than just writing down how they calculated functional mix in this table, they need to discuss it in the text, as this is an important aspect of their work.
The authors transformed the resulting data to reduce skewness and rescaled to a 0-1 range. They then calculated the average value of eight node indicators as the node-value at each TOD and the average value of six place indicators as its place-value..
Table 3 shows the results for the two highest priority clusters. I doubt very much that readers outside of China will have any idea where the places listed are located and it would be helpful to show their location by circling the stations on the figures showing ratings of nodes and places. Also, rather than labeling the columns x1…., y1…. The authors should use shorthand terms for each factor (e.g., # metro lines, metro frequency, ….). I had to scroll back and forth through the document to figure out what the codes meant, and finally printed off Table 2 so that I could make sense of Table 3 – that should not be necessary.
The authors put considerable emphasis on methods, but the methods used here are very similar to those used in Reusser et al. (2008) so the contribution is in adding a case rather than in proposing a new method. Also, I don’t think that it is necessary to explain how the silhouette method for identifying the number of clusters works and is applied - the silhouette method is a popular approach and it is easy to find articles and tutorials explaining it if a reader wants to do so.
On the other hand, the authors spend little time discussing a basic assumption of their work, that balance in each TOD is a good thing and can be measured in terms of transportation and land development. This is an assumption that Bertolini’s work makes, but as discussed in the Reusser paper, it might better be used as a starting point for discussion than as a hard and fast problem identifier. Metro stations often serve places that are specialized and some of these places might not be suitable for a full range of land uses (e.g., airports, heavy industrial zones) or might be most effective if scaled or clustered so as to require most or all of the space within a 500 meter radius around the station (e.g., a financial district, a government center, a university, a regional park.) Some areas do not want to encourage car use or parking in the immediate vicinity of a TOD. Thus, not every successful or important TOD will have a balance of land uses around it or substantial auto access. If the analysis finds an imbalance between the level of development around the station and the amount of transport service, the next step might well be to evaluate whether the station area is overdeveloped, underdeveloped, needs more transport service given its level of development, could increase both transit and land development levels, etc. It may well be that there are other factors that need to be brought into the discussion, for example, protection of the environment or historic preservation or resident preferences or business needs.
A related issue is that highly aggregate land use descriptors make it difficult to evaluate the efficacy of the TOD as a good place to live or work. For that, a finer grained analysis is needed. For example, the 15 min. city planning is usually based on providing the services that households use daily or weekly within a 15 min. trip (such as grocery shops)
The authors should either discuss these matters or acknowledge that their omission is a limitation of the work.
Finally, while the paper can be understood, it would benefit from editing to remove repetition, correct grammar, fill in missing words, etc. And I think the authors mean to say that Hefei’s population is 8 million, not 81 million. (‘The permanent population of Hefei had reached 81.89 million by 74 the end of 2019, an increase of 102,000 over the previous year according to the data of the 75 Hefei Municipal Bureau of statistics.”)
Overall, I think the paper is a useful case and with some edits should be published.
Author Response
Response to Reviewer 2 Comments
Point 1: The node-value of the transit stop describes accessibility of each “TOD”, with the authors considering metro, bus, and auto access. For place-value, the authors considered the area within 500 meters of each station, apparently measuring square meters of six highly aggregated land uses. How this is measured needs clarification because Table 2 indicates it’s the area of land devoted to each land use type whereas the text says, “Some researchers directly calculate the geometric area of each land-use type in the study area to reveal the activity intensity [32]. Therefore, this paper follows the same method to calculate the area of six different land uses for measuring the place-value.” Is it land area or land use area?
Response 1: In the revised version, we have made it clear that the place-value was obtained by calculating the land area. At the same time, the measurement in Table 2 was also changed to calculate the land area.
Point 2: In addition, at 156-157 the authors state, “This study selected several indicators to make the node-place model operable. As shown in Table 1 [sic].” Table 1 lists number of residents, number of workers, and degree of functional mix as the indicators for place, whereas Table 2 lists land areas of various types as place indicators along with the functional mix. The authors need to clarify what measures they actually used.
Response 2: For the different calculation methods of place-value, we have added more information to explain why the calculation methods are different from those in Table 1. At 261-264.
“However, the census data of Hefei city released the population of the whole city, and there is no accurate data within 500 meters at each TOD. Other statistical methods need to be selected to better reflect the activity intensity in small areas.”
Point 3: Table 2 lacks clarity in other ways. It appears the authors skipped D4 in the right hand column (got their numbering wrong.) Also, rather than just writing down how they calculated functional mix in this table, they need to discuss it in the text, as this is an important aspect of their work.
Response 3: First, we correct the wrong order in Table 2. Now, these values are arranged correctly. Secondly, we described the functional mix at 269-272 and explain its importance.
“Besides, the land function mix is one of the important indicators in calculating the place value. It represents the degree of land-use mix in the TODs calculated based on the land area of different land-use types, such as D1, D2, D3, D4, D5, and D6.”
Point 4: Table 3 shows the results for the two highest priority clusters. I doubt very much that readers outside of China will have any idea where the places listed are located and it would be helpful to show their location by circling the stations on the figures showing ratings of nodes and places. Also, rather than labeling the columns x1…., y1…. The authors should use shorthand terms for each factor (e.g., # metro lines, metro frequency, ….). I had to scroll back and forth through the document to figure out what the codes meant, and finally printed off Table 2 so that I could make sense of Table 3 – that should not be necessary.
Response 4: We are sorry for the inconvenience. In order to make the table easier to understand, we split the previous table 3 into two parts, showing node and place (Table 3a, Table 3b) respectively, and adding the abbreviation of each indicator. At the same time, we added the names of important TODs in Figure 4 and Figure 7, and added Figure 8 to explain the distribution of priority TODs in Hefei.
Point 5: The authors put considerable emphasis on methods, but the methods used here are very similar to those used in Reusser et al. (2008) so the contribution is in adding a case rather than in proposing a new method. Also, I don’t think that it is necessary to explain how the silhouette method for identifying the number of clusters works and is applied - the silhouette method is a popular approach and it is easy to find articles and tutorials explaining it if a reader wants to do so.
Response 5: We revised this inappropriate expression, and then deleted the introduction of the silhouette method and replaced it with a reference to the original paper. At 287-301.
Point 6: On the other hand, the authors spend little time discussing a basic assumption of their work, that balance in each TOD is a good thing and can be measured in terms of transportation and land development. This is an assumption that Bertolini’s work makes, but as discussed in the Reusser paper, it might better be used as a starting point for discussion than as a hard and fast problem identifier. Metro stations often serve places that are specialized and some of these places might not be suitable for a full range of land uses (e.g., airports, heavy industrial zones) or might be most effective if scaled or clustered so as to require most or all of the space within a 500 meter radius around the station (e.g., a financial district, a government center, a university, a regional park.) Some areas do not want to encourage car use or parking in the immediate vicinity of a TOD. Thus, not every successful or important TOD will have a balance of land uses around it or substantial auto access. If the analysis finds an imbalance between the level of development around the station and the amount of transport service, the next step might well be to evaluate whether the station area is overdeveloped, underdeveloped, needs more transport service given its level of development, could increase both transit and land development levels, etc. It may well be that there are other factors that need to be brought into the discussion, for example, protection of the environment or historic preservation or resident preferences or business needs.
Response 6: This comment has brought us great inspiration. Based on this suggestion, we rewrote the discussion section. The revised version indicated that the future development direction of priority TODs needs to consider their respective service functions and needs to be discussed in categories.
“While the above results can explain the development priorities of TODs based on node-place model results, there is a noticeable difference in the indicators that need to be developed among TODs in the same priority group, as shown in Tables 3a and 3b, due to the specialized nature of certain TODs. For example, Hefei South Railway Station is a transportation hub mainly spatialized in the distribution of goods and passenger transfer services, which drives the economic development of the region. In Hefei South Railway Station TOD, the development of commercial activities should be encouraged, and parking needs must be met. But industrial or administrative activities do not have the same high priority of development. The Gongdafeicuihuxiaoqu mainly serves surrounding universities. Promoting further diversification of activities is not possible within 500 meters of that TOD. Therefore, understanding TOD's service attributes are the basis for accurately understanding TOD's development direction and formulating TOD's development strategy. The future development strategies of TODs need to consider the local conditions. The purpose of this research was to first understand the unbalanced situations in some TODs by examining the relationship between accessibility and activity intensity and then prioritize development based on the distance from a balanced status. While this strategy can group a broad range of TODs based on the balanced development of land-use and accessibility at each TOD, further research is necessary to understand the priority TODs among spatialized TODs that cannot have a full range of land uses or do not require a full range of transport options.”
Point 7: A related issue is that highly aggregate land use descriptors make it difficult to evaluate the efficacy of the TOD as a good place to live or work. For that, a finer grained analysis is needed. For example, the 15 min. city planning is usually based on providing the services that households use daily or weekly within a 15 min. trip (such as grocery shops)
Response 7: We explained this problem in the limitation part of the paper, and stated that other methods could be combined for analysis in future research.
“This paper only considered the traffic accessibility and the surrounding activity intensity to measure the priority TODs. But the development of TOD from the perspective of TOD users, such as TOD as a living and working environment, is highly important to achieve the development goals of TODs. The 3D (density, diversity, and design) principle [45] of TOD development suggests the integration of design into TOD development models. Fully understanding the development priority at each TOD requires broad considerations such as design, history, and natural value at TODs. These are the limitations of this research as a study to find priority TODs that need the attention of future research.”
Point 8: while the paper can be understood, it would benefit from editing to remove repetition, correct grammar, fill in missing words, etc. And I think the authors mean to say that Hefei’s population is 8 million, not 81 million. (‘The permanent population of Hefei had reached 81.89 million by 74 the end of 2019, an increase of 102,000 over the previous year according to the data of the 75 Hefei Municipal Bureau of statistics.”)
Response 8: We re-examined every sentence of the paper and tried to avoid these errors in the revised paper. At last, thank you very much for your precious comments!
Author Response File: Author Response.docx
Round 2
Reviewer 1 Report
It is considered that the new version presented by the authors gives an adequate answer to the main questions previously presented.
