## 3 Link Budget and Dual-Slope Path Loss Measurement Results
### Dual-Slope Path Loss Model Results
In addition, the largest exponents of PLE for the second slope occurred in suburban environments at 700 MHz and 5.9 GHz. Note that for the suburban environment at 700 MHz and 5.9 GHz, constructive interference was observed for the first slope due to the multipath effect. This was also observed for the urban environment with high traffic density at 700 MHz. \begin{table}
\begin{tabular}{c c c c c c c} \hline \hline \multirow{2}{*}{**Scenario**} & \multicolumn{5}{c}{**700 MHz**} \\  & \(\tau_{\mathbf{1}}\) & \(L_{\mathbf{0}}\) (dB) & \(\sigma_{\mathbf{S_{1}}}\) (dB) & \(\tau_{\mathbf{2}}\) & \(\sigma_{\mathbf{S_{2}}}\) (dB) & \(d_{C}\) (m) \\ \hline
1 (Urban H-D) & 1.45 & 37.34 & 4.52 & 3.43 & 5.00 & 35.16 \\
2 (Urban L-D) & 2.13 & 31.42 & 5.47 & 3.76 & 6.66 & 35.44 \\
3 (Suburban) & 1.04 & 38.78 & 4.28 & 4.92 & 5.67 & 58.40 \\ \hline \multirow{2}{*}{**Scenario**} & \multicolumn{5}{c}{**5.9 GHz**} \\  & \(\tau_{\mathbf{1}}\) & \(L_{\mathbf{0}}\) (dB) & \(\sigma_{\mathbf{S_{1}}}\) (dB) & \(\tau_{\mathbf{2}}\) & \(\sigma_{\mathbf{S_{2}}}\) (dB) & \(d_{C}\) (m) \\ \hline
2 (Urban L-D) & 2.46 & 45.88 & 4.49 & 6.26 & 5.01 & 132.42 \\
3 (Suburban) & 1.72 & 52.40 & 4.80 & 9.69 & 5.25 & 306.04 \\ \hline \hline \end{tabular}
\end{table} 
Table 2: Parameters obtained at 700 MHz and 5.9 GHz. Figure 8: Path loss as a function of Tx/Rx separation distance for an urban environment with high road traffic density at 700 MHz. Figure 9: Path loss as a function of Tx/Rx separation distance for an urban environment with low road traffic density at 5.9 GHz. With respect to the large-scale fading modeled by the parameter \(\sigma_{S}\), the received signal suffered the highest variations in urban with low traffic density and suburban environments at 700 MHz and 5.9 GHz. On the other hand, the critical distance ranges from 35.16 m to 58.40 m at 700 MHz, with the largest critical distance obtained in a suburban environment, while the critical distance at 5.9 GHz varies from 132.42 m to 306.04 m for urban with low traffic density and suburban environments, respectively. It should be noted that in our measurement campaign, there are very few records and scenarios where dual-slope behavior occurred in the path loss propagation analysis. Similarly, only a very small number of researchers have shown results from dual-slope models for vehicular applications [18; 26; 27; 28; 29; 30]. Table 3 summarizes the values of the dual-slope path loss exponent and the standard deviations of shadowing derived from channel measurement campaigns conducted in different vehicular environments. These results can be used in vehicular network simulators to design, evaluate, and validate new protocols that improve the quality of vehicular communication systems and enable the integration of ITS, AD, and vehicular sensing with the 5G-IoT ecosystem. The results obtained in this work show the influence of the frequency band and the propagation environment on the estimated values of the path loss propagation and the critical distance. Therefore, when deploying sensor networks for ITS applications in real conditions, the propagation scenario must be considered. According to the results presented in this paper, it is necessary to take into account that urban scenarios with low traffic density have more path loss propagation values for the first slope, up to the critical distance. Similarly, it should be noted that the path loss increased significantly from the critical distance for all propagation environments analyzed in this study at 700 MHz and 5.9 GHz.