**7. Conclusions**

Literature and the empirical evidence have demonstrated the convenience of providing GI in cities. GI requires physical spaces and the actual implementation of GI in cities has been proved to be difficult and challenging, especially in finding areas to be devoted to that end. Streets have been found as a convenient location for GI in urban areas. Based on three cities in the US that advanced in the planning, design and implementation of green streets, this paper explored the green streets processes and reported the evolution of the traditional street design routine.

The main outcome of this research is the identification of common elements in the design process among the case studies. The green street design process includes various steps and addresses different issues at different scales; it is a complex, multi-scale, multiagency, interdisciplinary, stepwise process, that requires a longer time frame and the development of a specific legal framework. We have found that the word "planning" appears necessarily attached in the green street design process. A framework for a green street planning and design procedure was presented and discussed in the paper.

This paper contributes to enriching the discussion and reporting cases with actual green streets. The street design process reported, guided by the stormwater managemen<sup>t</sup> approach, is a confirmation of the existence of the environmental function of the street and confirms the ROW allocation conflict. At the same time, this study provides a glimpse or a sense that there is a substantial amount of underutilized space within ROW, which can be optimized through careful multifunctional design. The cases show that there are possible ways to allocate spaces within the ROW, without reducing the capacity or diminishing the level of service for other traditional street uses.

As final recommendations, cities can explore the transformation of current ROW into green streets as a smart way to deal with many current problems or situations (e.g., the deficit of green areas or adaptation to climate change). Since qualitative research is interpretive and contextual, it is suitable to describe phenomena rather than provide conclusive results. The presented planning and design process associated to green streets, rather than providing an applicable method, should be seen as inspiration to guide similar processes in other cities, learning from the good and the bad experiences of the three cases presented.

**Author Contributions:** Conceptualization, A.R.-V.; methodology, A.R.-V.; software, A.R.-V., H.A.O.-R.; formal analysis, A.R.-V.; investigation, A.R.-V., H.A.O.-R.; resources, A.R.-V.; data curation, A.R.-V.; writing—original draft preparation, A.R.-V., H.A.O.-R.; writing—review and editing, A.R.-V., H.A.O.-R.; visualization, A.R.-V., H.A.O.-R.; supervision, A.R.-V.; project administration, A.R.-V.; funding acquisition, A.R.-V. All authors have read and agreed to the published version of the manuscript.

**Funding:** This research received no external funding.

**Acknowledgments:** The authors are grateful for the support received by MINCIENCIAS, Fulbright-Colombia, The Institute of Transportation Studies of the University of California, Davis and the Vice-presidency of Research and Creation at Universidad de los Andes.

**Conflicts of Interest:** The authors declare no conflict of interest.
