# Smartphone Sensors in Motion: Advancing Traffic Safety with Mobile Technology
## 3 Results
### Measurement Results for the Dry Road  
All measurements were tabulated for the purpose of evaluating and comparing values between devices. The Table 4 displays the average values measured by the devices for each speed. Additionally, an average has been calculated for the overall measurements on the dry road surface. The differences between each smartphone and the XL Meter are also presented. These differences were evaluated in their absolute value and overall percentage value. It can be observed that the Mate 20 smartphone exhibited the closest percentage value to the XL meter. The Redmi 5G and 11T smartphones exhibited similar percentage difference values. A graphical comparison (Figure 9) of the values measured by each device reveals that at a speed of 30 km/h, the overall measured values are higher than at 50 km/h. For two of the smartphones, the measured values are greater than those for the XL Meter, while for one smartphone, the measured values are lower than those of the XL Meter. Overall, it can be seen that the values measured by the smartphones are not that different from the values measured by the XL Meter. For measurements taken at higher speeds, the trend is consistent with that observed at lower speeds. The Huawei Mate 20 and Xiaomi 11T were able to achieve values that were comparable to those measured with the XL Meter. The Xiaomi Redmi 5G device exhibited similar behavior at lower speeds, with values that were lower than those observed for the other smartphones and the XL Meter. \begin{table}
\begin{tabular}{c c c c c} \hline \hline
**Velocity** & \multirow{2}{*}{**XL Meter**} & \multicolumn{3}{c}{**Device**} \\
**[km/h]** & & **[m/s2]** & **[m/s2]** & **Redmi 5G** & **11T** \\ \hline
30 & 10.34 & 10.66 & 10.04 & 10.82 \\
50 & 10.28 & 10.44 & 9.87 & 10.73 \\
70 & 10.54 & 10.60 & 9.97 & 10.89 \\
90 & 10.57 & 10.80 & 9.90 & 11.01 \\ Average & 10.43 & 10.63 & 9.95 & 10.86 \\ Difference & - & 0.19 & 0.49 & 0.43 \\ Difference in \% & - & 1.81 & 4.90 & 3.96 \\ \hline \hline \end{tabular}
\end{table} 
Table 4: Evaluation of the measurements on the dry road. Figure 9: Comparison of the average values for the dry road. The graph (Figure 10) illustrates the individual values measured by the equipment on a dry road. It also demonstrates the differences between the XL Meter and smartphones. The overall average values are within 0.5 m/s\({}^{2}\). Overall, the data indicate that the smartphones do not deviate by more than 5% from the XL Meter. A comparison of the standard deviation is presented in Table 5 This table illustrates how the values varied at dry road speeds. At a speed of 30 km/h, the largest standard deviation values were recorded, reaching as high as 0.4. However, the difference between the XL Meter and the smartphones is not significant. At the remaining speeds, the standard deviation no longer reaches high values. This demonstrates the overall discrepancy between the mean values at all speeds, where the differences between the smartphones and the XL Meter are minimal. The percentage comparison reveals elevated values, which is a consequence of the low standard deviation. It can be observed that the optimal device in this instance is the 11T smartphone. Figure 11 illustrates the trend in the standard deviation when measured on the dry road. At a speed of 30 km/h, the standard deviation values were at the highest level of all the measurements on that surface. The values at this speed fluctuate slightly between the devices but are not significantly different. In contrast, the standard deviation values for the other measurements on the dry road are at their lowest level, indicating that the measurements are nearly identical to the average values. While slight differences can be observed on the graph at 70 km/h, these are not significant. Figure 10: Comparison of the average values and differences on the dry road.