## 3 Interview Results
### Adaptability and Optimization Requirements of Intelligent Voice Assistants  
Drivers' adaptability to intelligent voice assistants and their expectations for optimization are key factors in enhancing the effectiveness of fatigue driving prevention. Analysis of interview data revealed that the adaptability of voice assistants significantly influences drivers' evaluations and directly impacts their fatigue-related behaviors.  
Firstly, most drivers expressed dissatisfaction with current voice assistants, particularly regarding their interactive experience. Many reported that the assistants' voice interactions felt rigid, lacked personalization, and sometimes became irritating due to excessive interruptions. For instance, P04 (a long-haul truck driver) remarked, _\"Sometimes the assistant sounds too robotic and asks very basic questions that don't meet my actual needs--it just feels like a machine talking\"_. [PERSON] (a taxi driver) echoed this concern: _\"The assistant keeps repeating the same information, which gets annoying. Especially during long drives, this repetition makes my fatigue feel even worse\"_. These responses indicate that current voice assistants lack flexibility and personalization, failing to adequately consider drivers' real-time needs and emotional fluctuations.  
Ideally, drivers expect voice assistants to have a friendlier tone, appropriate speech speed, context-aware responsiveness, and personalized recommendation functions. For example, P12 (a taxi driver) noted, _\"It would be great if the assistant could adjust its tone and pace based on how tired I sound--like using a softer voice when I'm fatigued\"_. P05 (a long-haul truck driver) hoped that the assistant could provide personalized suggestions based on road conditions, weather, and time, while minimizing unnecessary reminders and information overload. Such improvements would not only help reduce driver fatigue but also enhance the emotional connection between the driver and the assistant, thereby supporting better focus during driving.  
Regarding optimization directions, different fatigue states entail different expectations for voice assistant behavior. For severely fatigued drivers, high-stimulation dialogue--such as humorous or lively interactions--is needed to energize them and reduce drowsiness. As P02 (a long-haul truck driver) explained, _\"When I'm really tired, if the assistant tells a joke or asks something funny, it helps me feel a bit less exhausted\"_. For drivers experiencing mild fatigue, low-intensity social dialogue--such as casual chatting or simple Q&A--can effectively relieve stress. P17 (a ride-hailing driver) commented, \"_I like having light interactions with the assistant, like chatting with a friend--it helps me relax a bit\"_. Meanwhile, for drivers without any obvious fatigue, the assistant should maintain minimal intervention to avoid unnecessary disturbance. P21 (a private car owner) remarked, \"_If I'm not tired, the assistant shouldn't bother me too often--just give information when I need it\"_.  
Additionally, the frequency of assistant interventions should be tailored to the driver's fatigue level. For those who are severely fatigued, increased intervention may be necessary but should not excessively disrupt attention. For mildly fatigued drivers, moderate reminders can help alleviate fatigue. For those not experiencing fatigue, the assistant should maintain a low frequency of interaction, offering reminders only when needed. This demand-driven intelligent intervention strategy not only avoids unnecessary interference but also provides the most appropriate support according to the driver's real-time state.