## 3 Tests
### System Performance  
Shown below are the results of two of the tests carried out. The first corresponds to a scenario 1 manoeuvre (Figure 5) in which vehicle V2 is stopped in the lane. Vehicle V1 is approaching it at a speed of over 30 km/h and automatically overtakes as no other obstacles have been detected in the left-hand lane to impede it (Figure 6). It should be noted that the position relative to the scanner of the points detected for obstacle V2 varies in the two coordinates. This is because as vehicle V1 approaches, it also overtakes leaving the obstacle to its right. However, at the instant vehicle V1 starts its manoeuvre it issues a warning to vehicle V3 moving behind it, whose driver proceeds to reduce speed until it stops behind vehicle V2 (Figure 7). Finally, Figure 8 shows how the steering wheel of vehicle V1 evolves during the automatic overtaking manoeuvre. \begin{table}
\begin{tabular}{|c|c|c|} \hline
**Vehicle** & **Instrumentation** & **Information** \\ \hline \multirow{8}{*}{V1: Vehicle including the surroundings detection system} & Laser scanner Sick LRS 1000 & Obstacle position \\ \cline{2-3}  & Trimble R4 RTK GPS receiver & Position on the digital map \\ \cline{2-3}  & RMS FES 33 & Longitudinal and lateral \\  & Gyroscopic platform & accelerations, yaw angle \\ \cline{2-3}  & Bus Can Vector & Speed, steering wheel, \\ \cline{2-3}  & CANcaseXL interface & accelerator pedal \\ \cline{2-3}  & Wireless communication module & Warnings issued to \\ \cline{2-3}  & Human Machine Interface & \\ \hline \multirow{3}{*}{V2: Vehicle detected as obstacle} & Topcon GB-300 GPS receiver & Position \\ \cline{2-3}  & Bus Can Vector & Speed \\ \cline{2-3}  & CANcaseXL interface & \\ \hline \multirow{8}{*}{V3: vehicle moving behind the system-equipped vehicle} & Garmin GPS & Position \\ \cline{2-3}  & eTrex H receiver & \\ \cline{2-3}  & Bus Can Vector & Speed \\ \cline{2-3}  & CANcaseXL interface & \\ \cline{2-3}  & Wireless communication module & Receipt of warnings \\ \cline{2-3}  & & issued by V1 \\ \cline{2-3}  & Human Machine Interface & \\ \hline \multirow{3}{*}{V4: vehicle moving along the left-hand lane in the opposite direction} & Astech G-12 GPS receiver & Position \\ \cline{2-3}  & \multicolumn{1}{c|}{} & \\ \cline{2-3}  & Astech G-12 GPS receiver & Position \\ \cline{2-3}  & \multicolumn{1}{c|}{} & \\ \cline{2-3}  & Wireless communication module & Receipt of warnings \\ \cline{2-3}  & \multicolumn{1}{c|}{} & \\ \cline{2-3}  & Human Machine Interface & \\ \hline \end{tabular}
\end{table} 
Table 2: Vehicle instrumentation. Figure 5: Vehicle paths during the manoeuvre. Figure 6: Laser scanner detection during the test. The second test corresponds to scenario 2 in which vehicle V2 is moving at an abnormally slow speed and vehicles V1 and V3 are approaching from behind (Figure 9). Vehicle V1 detects that obstacle but also identifies another vehicle V4 moving along the left-hand lane in the opposite direction (Figure 10), which prevents the vehicle from overtaking. For that reason, it automatically reduces speed to adapt its speed to that of vehicle V2 and issues a warning to vehicle V3 that is following it and whose driver also proceeds to adapt their speed (Figure 11). The automatic action on the brake pedal of vehicle V1 (Figure 12) is consistent with the previous speed reduction. Figure 8: Steering wheel turning angle during the test. Figure 7: Vehicle speeds during the test. Figure 10: Laser scanner detection during the test. Figure 9: Vehicle paths during the manoeuvre. Finally, it should be noticed that in the case of the experiments related to the present paper, three vehicles are connected to the wireless network, and they circulate consecutively at distances of less than 100 m at speeds up to 50 km/h. In consequence, the real time performance of the network is warranted. The above examples make it clear that the assistance system works properly on three levels:  
* Obstacle detection and monitoring, identifying obstacles that pose a risk.