Calibration of the Intelligent Driver Model (IDM) at the Microscopic Level

Round 1

Reviewer 1 Report

Comments and Suggestions for Authors

Comments on the text:

• it is not clear from the text at what frequency the driving data was collected (4.3 only mentions resampling of already collected data to 4Hz),
• in 5.2.1 the recording interval is stated as 4 s, for the other scenarios it is not clear (was the interval changed during the run, by section?),
• the 4 s interval does not correspond to the plots in Fig. 4 (my rough guess is that runs 1-4 lasted about 100 s which is 25 samples and what these plots do not correspond to),
• what values were worked with for desired distance/safety time?
• from line 363 onwards: it states that it concentrates on driver 2 ("to establish a practical range of values for each parameter" and "driver 2 executed acceleration and deceleration manoeuvres across a range of speeds, from very gentle to highly aggressive driving styles") and applies his style to the other drivers (e.g. : the ratio of UB and LB for parameter a is approximately 2.2 for all drivers and 2.6 for parameter b), which in turn leads to questioning the previous claim (e.g., for driver 1, Table 1 reports values of A=5.93, LB=3.18 and UB=8.33 for parameter b),
• the value in Table 1 for driver 2 and parameter b (2.26) is different from the one reported in the text on line 335 (2.08),
• it is not clear why Tab.1 for the All column does not give Average values, the values for LB and UB are suspicious.

Recommendations:

• in formula (1) explain the effect of δ (smoothness of the acceleration),
• I miss the discussion about the real use and the direction towards a universal IDM (maybe with parameterization for different real cases, e.g. also for the highway, possibly under different conditions, e.g. darkness, fog, ...)

Formal comments:

• the numbering of the paragraphs is incorrect,
• unify the font for speed (formula 1),
• line 124: missing bracket termination,
• specify some references (e.g.: [7] can be traced as both a DVD and a conference paper, details for [9], [16]; [17] has both ISBN and DOI assigned).

Author Response

Please find attached the point-by-point response to the reviewer 1.

Author Response File: Author Response.pdf

Reviewer 2 Report

Comments and Suggestions for Authors

This work presents an observational research aiming to provide a calibration technique for the Intelligent Driver Model (IDM) car-following model that considers the physical interpretation of each parameter. To achieve this objective, instrumented vehicle and trajectory data was gathered for a group of Portuguese drivers.

 

The paper is well-organized and clearly written, with a comprehensive literature review. The authors thoroughly outline the subject framework, identify gaps in existing research, and propose solutions. Additionally, the methodology is well-detailed, and the results are substantiated, valid, and properly analyzed. The conclusions drawn appear to be well-supported and justified.

 

The following comments aim to assist the authors in revising and improving their work:

 

- The research objectives should be explicitly stated.

- It would be helpful if any research questions addressed in the introduction section.

- The authors should provide a brief explanation of why this particular calibration technique was chosen. Is it the most suitable method for the analysis? Please clarify.

- Do you consider that the sample size of the dataset consists a "representative subset" for the purpose of your analysis? Five drivers is rather small sample size. Please explain.

- The authors should further elaborate on the paper’s contribution and its added value to both knowledge and practice.

- A connection of the aim of this study with the practical considerations in the end could become clearer and would help the reader understand how these objectives are pursued.

- The discussion should explore potential opportunities and challenges arising from this research.

- The limitations of the study should be clearly described.

Comments on the Quality of English Language

The English could be improved to more clearly express the research.

Author Response

Please see attached the point-by-point response to the reviewer 2.

Author Response File: Author Response.pdf

Round 2

Reviewer 2 Report

Comments and Suggestions for Authors

All the changes that have been requested in the original review have been made in this updated version of the paper. Τhe quality of the paper has reached the publishable standards and therefore, it can be accepted for publication.