# Influence of Headlight Level on Object Detection in Urban Traffic at Night
## 3 Results
### Photometric Results
Looking at Tables 4 and 5, which contain the determined Visibility Levels for test road 2, it can be seen that with the low beam switched off all object positions have Visibility Levels of more than 7 for both vehicle position 1 and vehicle position 2; thus, the visibility conditions caused by the street lighting alone should be sufficient for detecting the objects. Furthermore, it can be seen that the effectiveness of the fully switched on low beam is significantly improved for test road 2, with a lower illumination level of 0.53 cd m\({}^{-2}\) compared to test road 1 (0.91 cd m\({}^{-2}\)). Thus, for both vehicle positions, there is no object position where the Visibility Level is less than 1. This means that the threshold luminance difference from [PERSON]'s Small Target Visibility Model is achieved with fully activated low beam for all object positions. Compared to test road 1, the number of critical object positions with Visibility Levels less than 7 decreases from 9 to 3 out of 16 positions for vehicle position 1 and from 5 to 0 for vehicle position 2. \begin{table}
\begin{tabular}{c c c c c} \hline \hline  & \multicolumn{4}{c}{Low Beam off} \\ \hline  & 30 m & 45 m & 55 m & 65 m \\ \hline \(-\)3.0 m & 25.35 & 14.62 & 11.28 & 8.76 \\ \(-\)1.5 m & 27.75 & 16.47 & 10.31 & 7.23 \\ 0.0 m & 30.14 & 16.42 & 10.75 & 8.21 \\ 1.5 m & 21.80 & 21.03 & 16.73 & 16.00 \\ \hline \multicolumn{4}{c}{Low Beam fully switched on} \\ \hline  & 30 m & 45 m & 55 m & 65 m \\ \hline \(-\)3.0 m & 53.81 & 24.97 & 6.91 & 8.31 \\ \(-\)1.5 m & 74.27 & 23.82 & 8.96 & 6.46 \\ 0.0 m & 116.84 & 31.59 & 14.69 & 10.05 \\ 1.5 m & 93.59 & 23.24 & 12.53 & 2.84 \\ \hline \hline \end{tabular}
\end{table} 
Table 4: Calculated Visibility Levels for test road 2, vehicle position 1. The increase in the effectiveness of the low beam becomes even more apparent on test road 3, which is the darkest test road in the study (see Tables 6 and 7). Here, there is only one object position for vehicle position 1 and two object positions for vehicle position 2 with a Visibility Level lower than 7. On the other hand, it can be seen again that the negative contrast generated by the street lighting alone leads to a Visibility Level greater than 7 at all object positions for both vehicle position 1 and vehicle position 2, which should enable detection of the objects. Overall, the evaluation of the visibility level on the three test roads shows the following effects. On the one hand, it becomes clear that when the low beam is switched off the Visibility Level shows less variation across the different object positions, and is greater than the proposed VL of 7 [52,54] at all considered object positions. \begin{table}
\begin{tabular}{c c c c c} \hline \hline  & \multicolumn{3}{c}{Low Beam off} \\ \hline  & 30 m & 45 m & 55 m & 65 m \\ \hline \(-\)3.0 m & 29.72 & 19.38 & 10.90 & 10.20 \\ \(-\)1.5 m & 33.23 & 22.59 & 11.55 & 11.00 \\ \(0.0\) m & 40.42 & 27.04 & 13.55 & 12.10 \\ \(1.5\) m & 41.50 & 25.45 & 15.75 & 13.80 \\ \hline \multicolumn{5}{c}{Low Beam fully switched on} \\ \hline  & 30 m & 45 m & 55 m & 65 m \\ \hline \(-\)3.0 m & 67.73 & 25.64 & 15.31 & 8.80 \\ \(-\)1.5 m & 135.30 & 27.81 & 18.94 & 9.21 \\ \(0.0\) m & 94.41 & 28.66 & 15.18 & 6.84 \\ \(1.5\) m & 74.88 & 26.01 & 17.38 & 10.04 \\ \hline \hline \end{tabular}
\end{table} 
Table 6: Calculated Visibility Levels for test road 3, vehicle position 1. \begin{table}
\begin{tabular}{c c c c c} \hline \hline  & \multicolumn{3}{c}{Low Beam off} \\ \hline  & 20 m & 35 m & 45 m & 55 m \\ \hline \(-\)3.0 m & 32.83 & 22.16 & 21.38 & 13.34 \\ \(-\)1.5 m & 34.09 & 22.48 & 20.78 & 11.69 \\ \(0.0\) m & 36.98 & 22.38 & 18.85 & 8.87 \\ \(1.5\) m & 26.00 & 30.36 & 23.09 & 20.42 \\ \hline \multicolumn{5}{c}{Low Beam fully switched on} \\ \hline  & 20 m & 35 m & 45 m & 55 m \\ \hline \(-\)3.0 m & 70.15 & 52.23 & 18.66 & 9.82 \\ \(-\)1.5 m & 152.23 & 63.35 & 27.58 & 16.63 \\ \(0.0\) m & 247.55 & 72.39 & 39.44 & 21.67 \\ \(1.5\) m & 162.93 & 50.33 & 32.80 & 8.22 \\ \hline \hline \end{tabular}
\end{table}