## 5 Conclusions  
Two methods have been studied and proposed for the calculation of the international roughness index as efficient alternatives that manage to obtain near-reality results in the selected case study. They allow us to quantify the state of roughness on the pavement, in addition to obtaining as a derived result, a 3D model that is possible to review at any time, avoiding having to go to the place physically. This model can be used to evaluate the conditions of service of a road, allows for the extraction of parameters, which are indicators of their status, contributing to the maintenance and inspection process.  
This research provides modern technological techniques and tools to solve problems present in road maintenance, either by lowering the equipment-related costs needed to obtain high-precision results or also by reducing the time spent on measurements needed to achieve international roughness index results. To this end, a literature review was carried out considering general and specific documents, which review the characteristics and considerations of UAVs, photogrammetry, and SfM algorithms for the reconstruction of virtual models and their application in the engineering and construction industry. Moreover, the authors reviewed the current methodologies for obtaining the IRI, application, and use of computer programs that allow the analysis of virtual models and longitudinal profiles. It is concluded that the generated virtual model manages to represent the state of the pavement and is suitable for obtaining the longitudinal profile as well as the calculation of the IRI associated with it because the results obtained belong to the acceptable range of values for semi-new roads. In addition, a wave cutting value is proposed in the longitudinal profile filter equal to 8.3 m.  
There are limitations to the application of the proposed methods and are mainly based on the variability of the parameters that the user can consider when obtaining photographic information. This ranges from the type of camera used to the number of photos recorded and time spent on the UAV equipment's operation and affects the quality of the model created and, therefore, the quality of the longitudinal profile extracted. The application of the proposed methods will also be limited due to the weather conditions, which do not allow for optimal results.  
The future work to be carried out following this investigative line corresponds in the first instance to the realization of multiple models for the same route and others, in order to determine the variability that exists between virtual reconstructions and establish fixed parameters that must be used when wanting to obtain the IRI using the present methodology. In addition, it is recommended to adjust the cut-off value in the wave filter that best suits the different longitudinal profiles obtained.  
This paper represents the results of teamwork. [PERSON], [PERSON], and [PERSON] designed the research methodology. [PERSON] carried out the literature review, methods, and experiments. All of the authors worked on the results, discussions, and conclusions of the manuscript. Finally, [PERSON], [PERSON], and [PERSON] reviewed and edited the manuscript. All authors have read and agreed to the published version of the manuscript.  
This research was funded by CONICYT grant number CONICYT-PCHA/International Doctorate/2019-72200306 for funding the graduate research of [PERSON].  
The authors wish to thank the TIMS space (Technology, Innovation, Management, and Innovation) of the School of Civil Engineering of the Pontificia Universidad Catolica de Valparaiso (Chile), where part of the research was carried out. Furthermore, the authors acknowledge to the Ministry of Public Works from Chile.  
The authors declare no conflict of interest.