## 4 Methods--Survey Based  
To answer mentioned questioned before, a globally distributed study was rolled out in April 2021 and was finalized in November 2021. Realized as a global free-access online questionnaire, in an anonymous and self-hosted way, participants inside and outside China were asked to rate the state-of-the-art in-vehicle lighting systems, which are displayed in Figure 1, for the year 2021. Commonly used internet-access devices like notebooks, tablets or smartphones were used to complete the online survey by applying responsible web design techniques in dark-mode. To speed up the distribution, we shared a reference QR-code on social media platforms like Facebook, WhatsApp or WeChat. Since our target audience should be inside and outside China, participants could choose between English or Chinese as the operating language. Out of the in-vehicle lighting context, the focus of this study was set to ambient illumination only realized as line-shape lights, displayed in 10 different colors at eight different positions. In addition, six different dynamic pattern meanings should be assigned to each other. At the beginning of the survey, the user information was collected. These answerers can be used to identify:  
* Personal: Living country, living region, age class and genders. * Surroundings: Current weather condition, date and time of the day. * Driving experience: The time spent inside a vehicle during a normal week (without consider the COVID-19 pandemic), if a subject drove a vehicle before. * Social status: Age of subject's own vehicle, acceptable price for buying a new vehicle. * Color vision test: Necessary to confirm that all subjects have no color-blindness. - Contrast vision test: Necessary to make sure that all subjects were able to identify the displayed information in a proper way, since there was no external observation and verification possible. Only if a subject was able to answer all questions in a proper way the participant was forwarded to the in-vehicle lighting questions. These mandatory questions were divided in five categories. First the investigated colors are shown including their RGB color code values as listed in Table 1 according to the US department of transportation. For white, a clear rendered visual separation was focused, based on a multiple device pre testing. All colors for rating, compare Table 1, were presented at the door position, as displayed in Table 2 and the following two questions were raised:  
1. Color Preferences: People were asked to rate all 10 colors according to their preferences. Rating was performed on Likert-like scales with alternating five items (like-bit like-neutral-bit dislike-dislike) or four items (no neutral element). \begin{table}
\begin{tabular}{c c c} \hline \hline
**Color** & **Meaning in the Automotive Driving Context** & **Color Code in RGB** & **Spectral Properties** \\ \hline Red & Do no enter, wrong way sign, stop and yield driving. & 255, 0, 0 \\ Orange & Background color for temporary traffic control signs. & 255, 102, 0 \\ Yellow & Background color for warning signs. & 255, 204, 0 \\ Green & Background color for information and guide signs. & 0, 153, 0 \\ Cyan & Proposal of signal light color for autonomous driving. & 6, 206, 179 \\ Blue & Background color for travel service information signs. & 0, 0, 255 \\ Purple & Background color for electronic toll collection signs. & 102, 0, 153 \\ \hline Cold White & 10,000 K for cold white appearance, no driving context. & 207, 218, 255 \\ Warm White & 5000 K for warm white appearance, no driving context. & 255, 208, 206 \\ Neutral White & 6500 K for neutral white appearance, no driving context. & 255, 249, 253 \\ \hline \hline \end{tabular}
\end{table} 
Table 1: Color settings used in the online survey [31; 32]. 2. Color and Emotions: People were asked to rate the same 10 colors in the context of four different emotions, named as joy, fatigue, attention and relax. These emotions were selected out of the driving context. Rating was performed on Likert-like scales, as in question 1.