This paper investigates the comparative negligence ratio, which serves as the criterion for determining the allocation of damages between the at-fault party and the victim in traffic accidents. The comparative negligence ratio applied between drivers in traffic accidents has a profound influence on drivers' driving behavior, traffic culture, and the resulting social costs. Therefore, establishing an efficient comparative negligence ratio is crucial for fostering a sound traffic culture and reducing the social costs associated with traffic accidents. Through theoretical analysis using a chicken game model applied to a specific type of traffic situation—namely, when a driver with right-of-way encounters a driver violating traffic regulations without right-of-way at an intersection—this paper presents policy implications for comparative negligence ratios that minimize the social costs related to traffic accidents. Specifically, it demonstrates that the current comparative negligence ratio is set unfavorably for victims, and therefore, to facilitate smooth traffic flow and reduce social costs, the comparative negligence ratio needs to be changed to be significantly more favorable to victims. Furthermore, it shows that the current standards and principles related to comparative negligence are incomplete and unreasonable, creating problems with predictability and the resulting legal stability, and leading to higher legal costs. Therefore, theoretical support and practical collaborative efforts should be undertaken to establish rational and objective comparative negligence standards.