## 3 Results
### Example Application of the Methodology
#### 3.1.3 Evaluation Assessment
The average driver's speed is shown in the box plot in Figure 8. This examines how the actual speed changed with the C-ITS warning about the approaching public transport vehicle. Comparing the two passages, we can state a speed reduction (approx. 4 km/h) during the passage with the C-ITS unit. \begin{table}
\begin{tabular}{c c c c c c} \hline \hline
**Post-Ride Questions Related to** & **Mean Value** & **Median Value** & **Mode** & **Variance** & **Standard Deviation** \\ \hline HMI distraction & 3.23 & 3 & 4 & 1.03 & 1.01 \\ Usefulness & 4.31 & 5 & 5 & 0.90 & 0.95 \\ Safety increase & 3.85 & 4 & 4 & 0.97 & 0.99 \\ \hline \hline \end{tabular}
\end{table} 
Table 2: The results from post-ride questionnaires including specific questions on general and the use-case Public Transport Vehicle Crossing. Figure 7: Information registration. This trend could be also observed in Table 3 where we can see mean, maximum, and minimum speed in numbers. When driving with a C-ITS unit, drivers also had generally more uniform speed in common, which is visible on the smaller standard deviation (1.65 smaller with C-ITS) and the smaller range (by 1.17). Drivers tend to have lower average maximum speed (about 2.36 km/h) and lower average minimum speed (about 1.19 km/h) measured for all vehicles. When performing a T-test of the statistical significance of the difference between the mean values with a 95% confidence interval, the resulting \(p\)-value is equal to 4.23 \(\times\) 10\({}^{-9}\) and we therefore consider the results to be statistically different. When performing [PERSON]'s test for the speed of both rides, the \(p\)-value of the test was 3.43 \(\times\) 10\({}^{-8}\), so we can say that the probability of a difference caused by chance is minimal. The second KPI selected for comparison was driver acceleration which is shown in Figure 9 and Table 4. Acceleration comparison does not show large differences with the use of a C-ITS unit. In both cases, the acceleration is centered around zero acceleration. The maximum and minimum acceleration values do not indicate significant braking or acceleration. When using a C-ITS unit, greater uniformity of driver acceleration can be seen on the range (1.35 m/s\({}^{2}\) smaller with C-ITS) and standard deviation (0.17 m/s\({}^{2}\) smaller with C-ITS), as well as lower average braking before without a C-ITS device. The sharp braking, which is taken when the deceleration of 5 m/s\({}^{2}\) is exceeded during the evaluation rides, was not exceeded in either of the two passes. Figure 8: Box plot of speed for all tested vehicles. \begin{table}
\begin{tabular}{c c c c c c} \hline \hline  & **Mean Speed** & **Mean Max Speed** & **Mean Min Speed** & **Speed Range** & **Standard Deviation** \\  & **[km/h]** & **[km/h]** & **[km/h]** & **[km/h]** & **[km/h]** \\ \hline Without C-ITS & 16.71 & 30.26 & 5.70 & 33.43 & 9.36 \\ With C-ITS & 14.76 & 27.90 & 3.79 & 32.26 & 7.71 \\ \hline \hline \end{tabular}
\end{table} 
Table 3: Box plot of speed for all tested vehicles. On performing a T-test of the statistical significance of the difference between the mean values with a 95% truth interval, the resulting \(p\)-value is equal to 0.13, and the mean value of the acceleration can therefore be caused by a random phenomenon. On the other hand, when applying [PERSON]'s test for the speed of both rides, the \(p\)-value of the test was 2.16 \(\times\) 10\({}^{-5}\), so we can say that the probability of a difference caused by chance is very small. The results of the functional evaluation are divided into three parts according to the methodology. Lessons learned:  
The evaluation was carried out at a place where a tram comes out of dense forest. Because of that, it sometimes happened that the C-ITS message was not received in time. One solution could be a retransmission of RSU directly at the intersection. There are also few recommendations filled out by the drivers:  
to inform the driver of the remaining time to the tram crossing,
to inform on the tram speed.