## 8 Conclusions  
The proposed methodology has the advantage that it considers in a very detailed way the geometric characteristics of the road, which have an important influence on fuel consumption and emissions generation.  
The HDM-4 model was very useful for estimating emissions, as it is developed specifically for roads, and the information required allows for a bottom-up analysis according to the methodologies that are used worldwide to estimate emissions at a higher level of reliability.  
The results of CO\({}_{2}\) emissions allow the ability to propose the construction of two environmental indicators of pressure on transport corridors: (i) Tonnes of CO\({}_{2}\) per kilometer by corridor, and (ii) Tonnes of CO\({}_{2}\) per million tonnes-kilometer. The first indicator reflects the number of daily emissions in tonnes emitted into the atmosphere per kilometer of freight in the corridors analyzed, whilst the second represents CO\({}_{2}\) emissions per tonne per kilometer of goods transported in transport corridors analyzed.  
These indicators make it possible to establish a diagnosis of freight transportation emissions in Mexico and build a baseline, through which mitigation strategies to reduce GHG emissions can be proposed. This allows the generation of public and private policies to respond to climate change.  
The study shows that for Mexico, there is a growth trend in CO\({}_{2}\) emissions produced by road transportation. The results will establish appropriate scenarios to understand the behavior of emissions from freight transport in Mexico and its impact on climate change.  
Although the methodology requires multiple data for its analysis, these data are easy to obtain by road organizations; hence, the replication of this study will be very easy for other countries.  
Figure 6: Baseline CO\({}_{2}\) emissions from freight transportation in Mexico’s road corridors. Source: Own elaboration.  
The following phases of this research will be used to develop guidelines for decision-makers in the transport sector to help them choose between well-documented strategies to mitigate GHG emissions in the road sector as action against climate change and for optimal use of monetary resources.  
With this information, future scenarios can be constructed based on changes in model variables, such as an increase in the AADT or road deterioration through the IRI.  
To mitigate climate change, it is important to implement strategies to decarbonize transportation. Using e-fuels, hybrid electric vehicles and electrification (vehicles and infrastructure) could have potential benefits to reduce emissions in road transport corridors in Mexico. Moreover, for sustainability, it is important to consider environmental considerations in freight transportation.  
Methodology, J.F.M.-S., E.M.A.-G. and R.S.-E.; Investigation, J.F.M.-S., W.M.-M. and H.L.C.-G.; Resources, H.D.-A.; Writing--original draft, J.F.M.-S. and E.M.A.-G.; Writing--review & editing, S.A.O.-B.; Supervision, E.M.A.-G. All authors have read and agreed to the published version of the manuscript.  
This research was financed by the Mexican Institute of Transportation and the Michoacan University of San Nicolas of Hidalgo, through research funds, including the support of the National Council for the Humanities, Science and Technology.  
Not applicable.  
Data Availability Statement: Data is contained within the article.  
The authors declare no conflict of interest.