## 1 Introduction  
Road traffic accidents are events that arise from complex factors, and causes can be classified into human factors, vehicle factors, and road environment factors [1]. The human factor accounts for the largest share among the factors of traffic accidents. With advancements in road design engineering and automotive engineering, traffic accidents caused by road environment factors and vehicle factors have been decreasing, whereas accidents caused by human errors do not show such a decreasing trend. Traffic accidents involving human factors in South Korea accounted for 97.4% of cases in 2019, an increase from 95.9% in 1996 [2]. One of the reasons for the minimal change in the number of accidents caused by human errors is the decrease in the physical abilities of older drivers following the increase in the elderly population [3]. However, we address these issues in the context of naturalistic challenges on the road. A leading cause of road accidents related to human error is driver distraction. With the increasing use of cell phones, most drivers use cell phone applications while driving. Cell phone applications in the 21 st century provide drivers with positive functions such as route setting and forward traffic information, but they have also been found to have the negative effect of distracting attention, such as in the case of using a cell phone and listening to music while driving [4; 5; 6]. Since 2010, there has been another change in the driving environment--vehicles started being equipped with advanced driver-assistance systems (ADAS) to support drivers while driving. ADAS technology was developed to improve the safety and convenience of drivers, starting with the commercial deployment of forward collision warning (FCW) and lane departure warning (LDW) systems. In the past, methods of improving drivers' safety included improvement of road safety features or developing and implementing training programs for drivers. However, the introduction of ADAS has emerged as a new way of improving drivers' safety, and various types of ADAS have been developed with the increasing rate of ADAS use in vehicles. Among these different types of ADAS, FCW was the first to be deployed. FCW provides drivers with a warning via sound and vibration before a collision with a vehicle or a pedestrian, and collision risk information is presented mainly through sound in South Korea, the warning time is 2.5 s before the collision). Thus, the positive function of the technology fitting to the development intention of FCW was the prevention of rear-end crashes. The results of traffic accident data analysis in the United States indicated that road accidents were reduced by up to 12% with FCW installation [7]. Additionally, estimation of the avoidance time of drivers by reproducing the crash situation on test tracks with FCW installation pointed to an instant decrease of 14.3% in rear-end crashes [8]. These positive functions of FCW have led South Korea to mandate the installation of FCW for commercial vehicles since 2018. However, unfortunately, there was no decrease in traffic accidents of commercial vehicles. The reason for no decrease in the number of accidents despite the introduction of new safety technology may be the adverse function of human factors following the adoption of the technology. In a survey of drivers of vehicles fitted with ADAS including FCW, it was found that owing to reduced physical requirements during driving with ADAS installation, drivers paid less attention while driving [9]. Through various long-term studies, it was found that, unlike the case of road safety features in which the effects apply to nonspecific multitudes of drivers passing through a specific point and where only the positive functions of reducing traffic accidents are presented [10; 11; 12], ADAS differed in terms of the method and scope of its impact on drivers, as outlined in Table 1.  
ADAS is installed in vehicles to enable quick detection of dangerous situations for a single driver and supports vehicle control to avoid accidents.