## 4 Conclusions, Limitations and Future Work
It must be noted that the obtained values of the boundaries only apply for this study case because they are based on the obtained database and the Spanish technical requirements. The values of the class limits must be adjusted to each particular case because construction techniques, used materials, traffic, weather conditions, age of the pavement, preservation techniques, etc. differ from one country to another; however, the methodology and criteria for setting the class limits were designed to be applicable to any situation. The use of the geometric mean to obtain the global label for each category allows a performance penalty when one of the properties does not meet the technical requirements. Indeed, it must be underlined that the attainment of a D grade in terms of mechanical and functional performance means that the mixtures do not comply with the technical requirements; however, in terms of environmental performance, this label has a merely informative character and it only pretends to encourage the use of more sustainable technologies. The findings in this research clearly demonstrate that the developed labeling scheme shows promise; it allows not only the assignation of performance labels to any asphalt mixture based on its properties, but also the comparison of features between different asphalt mixtures for thin wearing courses. However, this research has its limitations, despite the efforts collected, data remained limited and there were challenges associated with setting the number of label classes and their boundaries. For this reason, the design of any label should involve the participation of multiple stakeholders in order to design a system that meets IMs' needs, raises compliance and acceptance, and overcomes the limitations found in this first attempt. In any case, the development of this labeling scheme is an appropriate tool to encourage the road construction industry to develop, build, and manage safe, durable, sustainable, and economic pavements; it is also flexible enough to be tailored to suit countries' specific requirements to ensure its use. In order to increase the potential of this tool, an attempt to develop performance curves of the different properties based on the collected data will be made in future works. Therefore, regression relationships that fit the design parameters of the mixture to performance variables (i.e., cracking resistance, disaggregation resistance, skid resistance, etc.) will be established for further performance label assignment. **Author Contributions:** Data curation, L.G.-G.; formal analysis, L.G.-G.; investigation, L.G.-G.; methodology, R.M. ; project administration, R.M. ; supervision, R.M. ; validation, R.M. ; visualization, L.G.-G.; writing--original draft, L.G.-G.; writing--review and editing, R.M. **Funding:** This research was co-funded by the Spanish Ministry of Economy and Competitiveness, through the call RETOS-COLABORACION 2015 of the National Program of Research, Development, and Innovation to face the challenges of society (RTC-2015-4025-4), within the National Scientific and Technical Research and Innovation Plan for the 2013-2016 period, and the European Union, through FEDER funds, which have the main objective of promoting technological development, innovation, and quality research. It also received funding from the Agency for Management of University and Research Grants of the Catalonia Government through the Industrial Doctorates Plan. **Conflicts of Interest:** The authors declare no conflicts of interest. The funders had no role in the design of the study; in the collection, analyses, or interpretation of data; in the writing of the manuscript, or in the decision to publish the results.