## 2 Evaluation Method
### Measurement  
As shown in Figure 7, the tunnel of the SOC Evaluation Research Center (located in Yeoncheon-gun, Gyeonggi-do, Korea), which can realize fog and rainfall, and has a sufficient scale, was used as a facility for realizing bad weather. This facility can simulate fog and rain conditions in the form of a tunnel with a length of 200 m, a width of 32.8 m, and a maximum height of 16.2 m. In the case of the fog device used in this study, it is installed on both sides of the road at 10 m intervals in the 200 m tunnel, and uniform fog density can be realized using fog oil and a diffusion fan. Rain nozzles are installed at 10 m intervals in the 200 m tunnel section and the maximum rainfall is 100 mm/h. Figure 8 shows the setup for the measurement. Two movable pedestrian targets (one white and the other black) were used for the test, and the color temperature convertible headlamps were fixed to face the pedestrian targets. In the case of measuring equipment, a luminance meter (CA-2000, Konica Minolta, Tokyo, Japan) for measuring the luminance of a pedestrian target and a visibility sensor (VPF-710, Biral, Bristol, UK) were installed to measure the visibility distance according to weather conditions. The luminance meter was set up in consideration of the driver's eye level, and the position of the visibility sensor was \begin{table}
\begin{tabular}{c c c} \hline \hline
**Target Position** & **Target Position** & **Description** \\ \hline \⃝1 & 5 m & Minimum distance to measure \\ \⃝2 & 12.5 m & Driving distance considering TTC 1.5 s, 30 km/h \\ \⃝3 & 25 m & Driving distance considering TTC 1.5 s, 60 km/h \\ \hline \hline \end{tabular}
\end{table} 
Table 2: Description of pedestrian target positions. Figure 5: Pedestrian type reflectors as pedestrian targets: Pedestrian target design (height 175 cm, width 92 cm, with four wheels attached below for convenience of movement. Figure 6: Pedestrian target position. placed outside the irradiation range of the headlight. This is to ensure that the near-infrared rays that may be included in the headlights do not affect the visibility sensor. When setting the climatic conditions, the luminance value of the reference light source was referred to in consideration of the error of the visibility system, and the test environment conditions were followed. In addition, to secure the objectivity of the luminance value, the measurement was carried out after 30 min with the reference light source turned on in consideration of the preheating and light quantity stabilization time of the reference light source. In the case of rain, measurements were started when the road surface was sufficiently wet after spraying for more than 10 min under rain conditions. The brightness condition of night external conditions was set to 1 lux or less by referring to Euro NCAP AEB night test conditions [26]. The test was conducted under 36 conditions as shown in Table 3, and the climatic conditions were clear, fog, and rain in this order. Figure 9 shows photos taken during actual measurement under clear, fog, and rain conditions, respectively, at 3000 K and target distance of 12.5 m. Figure 10 shows the case where only the color temperature is changed to 6000 K under the same conditions as in Figure 9.  
Figure 8: Measurement setup for the test: (**a**) Installation of measuring devices and pedestrian targets in the climate tunnel; (**b**) visibility sensor installed on the side avoiding the irradiation range of the headlight. Figure 7: Implementation of fog and rain conditions in the test facility: (**a**) Inside view of the climatic tunnel; (**b**) fog generator operation inside the tunnel; (**c**) rainfall by rain nozzles inside the tunnel.