# Individual Differences in Signal Perception for Takeover Request in Autonomous Driving
## 2 Related Works
### Individual Differences in Driving  
The influence of a personal background on driving task performance has been extensively studied, both in the context of manual driving and autonomous driving research. Age, gender, and experience are commonly investigated factors. These differences have been examined in various settings, ranging from laboratory-based signal detection studies to real-world driving tasks. As autonomous driving technology continues to evolve, considering the diverse characteristics of different individuals becomes increasingly important to create personalized vehicles. While it is not feasible to design warnings tailored to every individual difference or personal characteristic, it is feasible to include a representative sample of the target population when testing warnings [20]. A study by [PERSON] and [PERSON] examined individual differences in reaction time using a simple finger response task involving visual, auditory, and tactile stimuli [34]. The findings indicated that responses to tactile stimuli were generally faster than visual and auditory stimuli, while auditory responses were faster than visual responses. In terms of \begin{table}
\begin{tabular}{c c c c c c} \hline
**Author** & **Signal 1** & **Visual Stimuli** & **Auditory Stimuli** & **Tactile Stimuli** & **Result 2** \\ \hline \multirow{4}{*}{[PERSON] and [PERSON] [30]} & \multirow{4}{*}{V, A, T} & \(5\times 5\) cm nine red & \multirow{4}{*}{75 dB} & 3 actors (VBW32), \multirow{4}{*}{200 Hz sinusoidal, \multirow{4}{*}{45.4 cd/m\({}^{2}\)}} & \multirow{4}{*}{T \(>\) V} \\  & & LEDs, & & & \\  & & luminance & 2000 Hz & & amplitude 15 \(\upmu\)m \\  & & & 45.4 cd/m\({}^{2}\) & & \\ \cline{3-6}  & & & 70 dB & 3 actors (VBW32), \multirow{4}{*}{200 Hz sinusoidal, \multirow{4}{*}{45.4 dd/m\({}^{2}\)}} & \multirow{4}{*}{T \(>\) A} \\ [PERSON] et al. [7] & A, T & & & 2000 Hz & \\  & & & & & 3 \(\times\) 2 actors \\ \cline{3-6}  & & & 2700 Hz & (PicoVibe), & unimodal \\ \cline{3-6}  & & & 60 Hz & 4 actors (Vp216) & \\ [PERSON] et al. [31] & A, T & & 1 kHz & 64 Hz & T \(>\) A \\ \cline{3-6}  & & 23 red LEDs, & & & \\ \cline{3-6}  & & luminance 1.5 a.u. at & 60–68 dB & 150 Hz sinusoidal, \multirow{4}{*}{45.4 dd/m\({}^{2}\)} & \multirow{4}{*}{V, T \(>\) A} \\ [PERSON] et al. [32] & V, A, T & 30 mA, & (50–51 dB) & amplitude 18.8 V & V, T \(>\) A \\ \cline{3-6}  & & Brightness 45 lux & 70 dB & & \\ [PERSON] et al. [14] & A, T & & 8000 Hz & & \\ [PERSON] and & & Three 5 mm LEDs & 72 dB (lateral) & two vibration motors & \\ [PERSON] [33] & V, A, T & 41–53 lux & 79 dB (center) & 100–110 Hz, & A, T \(>\) V \\  & & 350 Hz & steering wheel & & \\ \cline{3-6}  & & & 2 actors & V, A conditions: \\ [PERSON] [29] & V, A, T & 200 \(\times\) 200 pixel, & 0–100 dB, & 250 Hz & younger adults \\  & red circle & 400 Hz & intensity 1–255 gain & & had shorter \\  & & & & 3 \(\times\) 3 actors & \\ \cline{3-6}  & & & & (DC vibration motors with & A \(>\) T \\ \hline \end{tabular} 1 V = visual, A = auditory, T = tactile, 2 A \(>\) B means that A resulted in a better participant response than B.  
\end{table} 
Table 1: Warning signals used in previous research. age differences, reaction times for both visual and auditory stimuli tended to be slower with increasing age. Furthermore, women exhibited faster reaction times compared to men [35]. It has been observed that women have a higher sensitivity to sound, perceiving even small changes in decibel levels [35]. Brain activity measurements have also shown that women exhibit higher activation in the right prefrontal cortex in response to noise compared to men [36]. Additionally, women tend to excel in discriminating rhythm and pitch changes compared to men [36]. These individual differences may similarly manifest in the signals provided by vehicles, and gender differences may also exist in the level of auditory cues. The number of older drivers aged over 65 years is increasing.