## 4 Results
### Results of the Estimated PV Potential from Solar EVs on Donghae Expressway  
Among the three cities (Sokcho, Gangneung, and Donghae) through which the Donghae expressway passes, insolation is the highest in Sokcho in the morning, highest in Gangneung in the afternoon, and generally lowest in Donghae during the summer solstice (Figure 6a). In contrast, Donghae had the highest insolation, and Sokcho and Gangneung had similar insolation (Figure 6b). In other words, the insolations of the three cities were different, and the ranking of the insolation of each city by season also differed. Therefore, the weather characteristics of the three cities should be reflected, rather than the weather characteristics of a specific city in the study area. Figure 6: Hourly GHI of three cities on the (**a**) summer solstice and (**b**) winter solstice. \begin{table}
\begin{tabular}{c c c c c c c} \hline \hline \multirow{2}{*}{**Date**} & **Time** & \multicolumn{2}{c}{**Section A**} & \multicolumn{2}{c}{**Section B**} & \multicolumn{2}{c}{**Section C**} \\ \cline{3-7}  & **(hour)** & **Pixel (ea)** & **Length (km)** & **Pixel (ea)** & **Length (km)** & **Pixel (ea)** & **Length (km)** \\ \hline \hline \multirow{8}{*}{Summer \(\text{Solstice}\)} & 07:00 & 195 & 5.85 & 183 & 5.49 & 100 & 3.00 \\  & 08:00 & 38 & 1.14 & 129 & 3.87 & 13 & 0.39 \\  & 09:00 & 15 & 0.45 & 31 & 0.93 & 8 & 0.24 \\  & 10:00 & 0 & 0.00 & 2 & 0.06 & 3 & 0.09 \\  & 11:00 & 0 & 0.00 & 0 & 0.00 & 1 & 0.03 \\  & 12:00 & 0 & 0.00 & 0 & 0.00 & 0 & 0.00 \\  & 13:00 & 0 & 0.00 & 0 & 0.00 & 0 & 0.00 \\  & 14:00 & 0 & 0.00 & 0 & 0.00 & 0 & 0.00 \\  & 15:00 & 0 & 0.00 & 1 & 0.03 & 12 & 0.36 \\  & 16:00 & 22 & 0.66 & 78 & 2.34 & 17 & 0.51 \\  & 17:00 & 142 & 4.26 & 98 & 2.94 & 110 & 3.30 \\  & 18:00 & 227 & 6.81 & 231 & 6.93 & 166 & 4.98 \\  & Average & 53 & 1.60 & 63 & 1.88 & 36 & 1.08 \\ \hline \hline \multirow{8}{*}{Winter \(\text{Solstice}\)} & 09:00 & 245 & 7.35 & 238 & 7.14 & 169 & 5.07 \\  & 10:00 & 210 & 6.30 & 194 & 5.82 & 144 & 4.32 \\ \cline{1-1}  & 11:00 & 168 & 5.04 & 158 & 4.74 & 107 & 3.21 \\ \cline{1-1}  & 12:00 & 150 & 4.50 & 146 & 4.38 & 98 & 2.94 \\ \cline{1-1}  & 13:00 & 166 & 4.98 & 164 & 4.92 & 114 & 3.42 \\ \cline{1-1}  & 14:00 & 195 & 5.85 & 202 & 6.06 & 138 & 4.14 \\ \cline{1-1}  & 15:00 & 228 & 6.84 & 252 & 7.56 & 163 & 4.89 \\ \cline{1-1}  & 16:00 & 238 & 7.14 & 262 & 7.86 & 182 & 5.46 \\ \cline{1-1}  & 17:00 & 245 & 7.35 & 271 & 8.13 & 184 & 5.52 \\ \cline{1-1}  & Average & 205 & 6.15 & 210 & 6.29 & 144 & 4.33 \\ \hline \hline \end{tabular}
\end{table} 
Table 5: Shaded regions on the Donghae expressway on the summer solstice and winter solstice calculated by shadow analysis. Table 6 presents the percentage of areas (roads) where power generation is not possible because of tunnels and shadows on the Donghae expressway at different times of the day on both the summer and winter solstices and the results of the evaluation of the PV potential that can be expected from driving a single solar EV. On both solstices, the proportion of roads with no power generation to the length of each road section was the highest in Section C, followed by B and A. The proportion of non-generating areas by road section ranged from 17.1% to 27.6% during the summer solstice and 29.8% to 37.1% during the winter solstice. This value can be interpreted as a loss (amount or percentage) in terms of PV potential. The average hourly power generation of the solar EVs on each road section was within the range of 0.031-0.074 kWh for the summer solstice and 0.037-0.053 kWh for the winter solstice. In Sections A and B, the average value of the generation potential on the summer solstice was twice that of the winter solstice, whereas, in Section C, the converse was observed. This is because of the different hours of power generation on the two days (11 h on the summer solstice and 8 h on the winter solstice) and the insignificant amount of power generation during the morning and evening hours of the summer solstice.