## 1 Introduction
The distance between the detection object and the center of the road did not change. In the dynamic case, the test person drove the vehicle along the test track at a speed of \(80\,\mathrm{km}\,\mathrm{h}^{-1}\). In both parts, the driver signalized the detection of the object by pressing a button and the detection distance was measured by GPS sensors. The results of the study demonstrate that older drivers have slightly shorter detection distances than younger drivers. Thus, the results regarding the negative effect of age on visual performance are confirmed. Furthermore, the results demonstrate that the driving task also influences the detection distance. Thus, in the quasi-static part of the test, higher detection distances were achieved at all eccentricities versus in the dynamic case. The field factor, which, analogously to the Visibility Level, represents the multiplier between laboratory and field tests, is in a range of 8.75 to 32 for the entire test group. Thus, significantly higher contrasts are required in real traffic situations for the reliable detection of the visual signs than in the laboratory. Based on the determined detection distances, which are on average about 90 m, no direct dependence of the detection distance on the eccentricity can be observed. Therefore, [PERSON] considered the contrasts required at the determined detection distances and calculated the required light intensity from this. Once again, the measured data was mirrored to take into account the object positions to the right and left of the roadway. The curve of the required light intensity for the detection object at a distance of approximately 90 m as a function of the horizontal object position is shown in Figure 4[34]. Looking at the luminous intensity curve in Figure 4, it is evident that the luminous intensity required to detect a pedestrian at a distance of about 90 m decreases as the eccentricity angle \(\Theta\) increases. Thus, the results from the field studies of [PERSON] [18] are qualitatively confirmed by the investigations of [PERSON] [34]. The studies conducted so far on the Visibility Level give an initial indication of the detection conditions required for nighttime road traffic in non-urban areas. However, dynamic field studies in particular have the disadvantage that the studies cannot be carried out reproducibly with several drivers and thus different conditions are present for each test run, which significantly influence the respective detection conditions. The present work is therefore intended to answer the following research questions in statically conducted field studies. 1. What Visibility Level is required for reliable object detection with a probability greater than 90 %? 2. What influence does the object's distance and angle have on the required Visibility Level? Figure 3: Dependence of the required object luminance \(L_{\text{O}}\) on the object size \(\alpha\) (**left**) and the eccentricity angle \(\Theta\) (**right**) according to [PERSON] [18]; both with increasing object size \(\alpha\) and with increasing eccentricity angle \(\Theta\) the object luminance \(L_{\text{O}}\) required for detection decreases; for both fit functions, the coefficient of determination \(\text{R}^{2}\) is greater than 0.99 [18].