**8. Conclusions**

In this article, a low carbon scenario (LCS) is proposed for the Mexican transport sector through the integration of 21 greenhouse gas (GHG) mitigation measures. As a result, we have an LCS that describes a transport sector transformation path characterized by structural changes in passenger and freight mobility; use of new mobility technologies, with electric motors; biofuels' introduction; price signals; and changes in transport practices, emission regulations, and urban planning.

The economic and environmental analysis of joint and parallel implementation of the selected mitigation measures shows, in year 2035, accumulated benefits for −240,772 MUSD, an average mitigation cost of −76.0 USD / tCO2e, and an accumulated value of GHG emissions' reduction of 3166 MtCO2e (equivalent to a reduction of accumulated GHG emissions of 46.3% when compared to BLS, an average annual reduction of 126.7 MtCO2, and a 59.3% reduction of GHG emissions relative to the BLS in the year 2035). We believe that the GHG reductions' portfolio of mitigation measures analyzed in this article will help Mexico, and other countries in the world, to establish more robust, more ambitious, and faster energy transitions to limit GHG emissions in this key sector to restrain global climate change. However, this article shows that the grea<sup>t</sup> challenge is to raise the significant investment required to achieve this energy transition in a very capital-intensive sector such as the transport sector, as shown by the Mexican case, where an accumulated investment of 64,326 MUSD is needed to establish a low carbon transport sector that will contribute to the actions to restrain climate change.

These results should be considered carefully since the interaction between the 21 mitigation measures is limited and restricted to one or two modes of transport at best, and the possible additivity effects of these measures were not studied and considered in this article. The representations of the measures were consequently assumed of linear nature, so our results turn out to be conservative and do not necessarily represent what could happen in the real-world transport systems. Taking into account the additive effects of the 21 mitigation measures analyzed, which would reflect the greater interactivity between transport systems and their non-linear nature, would result in an improvement in the overall results (cumulative emissions, emissions to the year 2035, cost-benefit, mitigation costs and investments) that we have presented in this article.

**Supplementary Materials:** The following are available online at http://www.mdpi.com/1996-1073/13/1/84/s1, Figure S1: Degradation factor in the use intensity per vehicle age, Table S1: Age composition of imported used vehicles per year of entry.

**Author Contributions:** J.M.I.-S. and F.M. conceived the presented study. Jorge Islas developed energy, economic and environmental assessment methodology, G.K.G.-A. performed the computations in LEAP, Jorge Islas supervised the study, F.M. wrote the original manuscript, J.M.I.-S. and F.M. performed the formal analysis of the mitigation measures. All authors discussed the results and contributed to the final manuscript.

**Funding:** Authors thank SENER CONACyT Energy Sustainability Fund projects 117808 and 246911.

**Acknowledgments:** Authors thank María de Jesús Pérez Orozco for the technical support in scenario simulation using LEAP model. Also, we thank to the editor Johnson Wang and the three anonymous reviewers for their valuable commentaries.

**Conflicts of Interest:** The authors, Jorge M. Islas-Samperio, Fabio Manzini and Genice K. Grande-Acosta declare no conflict of interest, also we declare that 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, an in the decision to publish the results.
