# Advancements in the Intelligent Detection of Driver Fatigue and Distraction: A Comprehensive Review
## 2 The Impact of Fatigue and Distraction on Driving Behavior  
The phenomenon of driver fatigue and distraction has become one of the most concerning issues in the field of traffic safety [17; 18]. Fatigue driving usually stems from long hours of driving or lack of sleep, leading to physical and mental exhaustion, slow reactions, decreased judgment, and problems such as inattention, increased reaction time, judgment errors, and confusion [19; 20]. On the other hand, distracted driving occurs during the driving process when the driver's attention is diverted from the task of driving due to external distractions or internal thoughts. Activities such as using a mobile phone, conversing with passengers, or adjusting the stereo can diminish a driver's alertness to the traffic environment and reduce their ability to respond to sudden situations, thereby increasing the risk of traffic accidents [21; 22]. Figure 1 illustrates the main causes and behavior patterns leading to driver fatigue and distraction. Regarding the effects of fatigued driving and distracted driving on driver behavior, scholars have mainly investigated these through two approaches: accident database analysis and experimental research. In terms of accident database analysis, [PERSON] et al. [23] analyzed driving data from 70,000 drivers, which included a signifi  
Figure 1: Reasons and behaviors that lead to driver fatigue and distraction. data. They discovered that the collision risk under fatigued driving is twice that under normal driving conditions. However, the limitation of this study is its failure to explore in depth the specific impact of different levels of fatigue on collision risk. Furthermore, [PERSON] et al. [24] revealed through statistical analysis of 685 traffic accidents that the probability of collisions significantly increases for novice drivers when they are distracted, particularly while using mobile phones. This study highlighted the differential impact of distraction types on accident risk, but required broader data to validate the generality of its conclusions. In experimental research, the convenience and safety of simulators have led to a broad focus on studying the impacts of fatigue and distraction on driving. [PERSON] et al. [25] used the n-back test task on a simulator platform to examine the effects of varying cognitive loads on driving behavior and detection response tasks. [PERSON] et al. [26] conducted experiments based on a simulator to compare the differences in speed control and lateral vehicle control capabilities between distracted and non-distracted drivers. However, it has been noted that the actual impact of driver fatigue on reaction capabilities in real driving situations is more significant than what is represented in simulator data [27]. Additionally, the reactions of drivers to visual distractions and interface interactions in real road environments show significant differences from those in simulated environments [28]. Thus, when assessing impacts and quantifying research, as well as devising safety warning and response plans, reliance should not only be on simulated data; real vehicle experiments should also be conducted. [PERSON] et al. [29] assessed the fatigue level of drivers using the Karolinska Sleepiness Scale (KSS) before real vehicle testing. Their analysis found that reaction time is positively correlated with level of fatigue, highlighting the actual impact of fatigued driving on safety. However, this study relied on subjective assessments, which may have introduced bias. [PERSON] et al. [30] analyzed real vehicle driving test data to study the impact of distracted driving on driving capabilities, finding that driver distraction reduces the driver's vehicle control capabilities and that this impact varies with the type of distraction, yet they did not fully explore the quantitative assessment of distraction level. In summary, fatigue and distraction phenomena severely affect driving behavior, increasing the risk of traffic accidents.