## 7 Modeling Baseline CO\({}_{2}\) Emissions  
The modeling of the baseline through Geographic Information Systems (GIS) was based on the main corridors. These maps allow visualization of where the highest concentration of CO\({}_{2}\) emissions per kilometer of freight transported exists. Figure 5 shows the model based on Google Maps, such as the annual emissions per kilometer (environmental indicator 1).  
\begin{table}
\begin{tabular}{c c c c c c} \hline \hline \multirow{2}{*}{**Number**} & \multirow{2}{*}{**ID Mexican Corridor**} & \begin{tabular}{c} **Length of Corridor** \\ **Analyzed** \\ **(Kilometers)** \\ \end{tabular} & \begin{tabular}{c} **CO\({}_{2}\)** \\ **Emissions** \\ **(Tonnes)** \\ \end{tabular} & \
\begin{tabular}{c} **Weight Daily** \\ **(Tonnes)** \\ \end{tabular} &
\begin{tabular}{c} **Indicator 2** \\ **\"Tonnes of CO\({}_{2}\) per million** \\ **tonne-kilometers\"** \\ \end{tabular} \\ \hline
1 & Mexico City-Nuevo Laredo & 2279.02 & 17,897.68 & 64,993 & 120.83 \\ \hline
1.1 & \(\bullet\) Ramal a Piedras negras & 543.12 & 961.82 & 19,320 & 91.66 \\ \hline
2 & Mexico City-Cd Juarez & 3656.52 & 13,687.80 & 26,912 & 139.10 \\ \hline
3 & Mexico City-Nogales & 4484.07 & 10,850.56 & 20,037 & 120.77 \\ \hline
3.1 & \(\bullet\) Ramal a Tijuana & 1057.24 & 1770.27 & 16,001 & 104.65 \\ \hline
4 & Manzanillo-Tampico & 2050.25 & 6804.20 & 61,085 & 54.33 \\ \hline
4.1 & \(\bullet\) Ramal a Lazaro Cardenas & 836.29 & 2733.26 & 31,478 & 103.83 \\ \hline
5 & Mexico City-Veracruz & 778.32 & 6224.61 & 47,055 & 169.96 \\ \hline
6 &
\begin{tabular}{c} Veracruz-Monterrey con ramal \\ a Matamoros \\ \end{tabular} & 1758.48 & 3920.84 & 22,400 & 99.54 \\ \hline
7 &
\begin{tabular}{c} Puebla-Oxaxaca-Cd. Hidalgo \\ \end{tabular} & 1581.65 & 2289.78 & 7231 & 200.21 \\ \hline
8 & Mexico City-Puebla-Progreso & 2408.43 & 8482.65 & 18,831 & 187.04 \\ \hline
9 &
\begin{tabular}{c} Peninsula de Yucatan \\ \end{tabular} & 1757.18 & 2068.97 & 9966 & 118.15 \\ \hline
10 & Corredor del Pacifico & 2387.46 & 1668.17 & 5213 & 134.03 \\ \hline
11 & Mazatán-Matamoros & 2423.63 & 5376.85 & 7205 & 307.91 \\ \hline
12 & Transpeninsular de Baja California & 2296.0 & 1727.22 & 7571 & 99.36 \\ \hline
13 & Altiplano & 1109.2 & 4524.24 & 15,604 & 261.40 \\ \hline
14 & Acapulco-Tuxpan & 1833.13 & 3345.52 & 15,343 & 118.95 \\ \hline
15 & Acapulco-Veracruz & 1453.51 & 3715.08 & 15,419 & 165.77 \\ \hline
16 & Circuito Transistmico & 953.25 & 1467.88 & 11,218 & 137.27 \\ \hline \multicolumn{5}{c}{Average} & & & 143.93 \\ \hline \hline \end{tabular}
\end{table}
Table 8: Indicator 2: Tonnes of CO\({}_{2}\) per million Tonnes-kilometer.  
Figure 5: Modeling of CO\({}_{2}\) emissions in the freight corridors. Source: Own elaboration using Google Maps.  
Based on the results obtained in the indicators and using the historical growth of heavy vehicles in the corridors, a trend line for freight transportation in Mexico can be constructed [54]. However, the prediction of a trend may not be fully accurate depending on the model used for forecasting [55].  
To estimate the growth rate in the freight transportation sector, the growth of the vehicle fleet and cargo transported (including the contraction due to the COVID-19 pandemic) was used, and from the period 2013 to 2020, we obtained a growth of 3.53%, which can be applied to forecasting the growth of emissions over the 2020 baseline estimate of 36.32 Megatonnes of CO\({}_{2}\) (99,517.4 tonnes daily). Figure 6 shows the growth of baseline CO\({}_{2}\) emissions in freight transportation in the main road corridors in Mexico.