Objectives: The road traffic safety situation around the world is not optimistic. The development of intelligent vehicles has become an ideal way to reduce road traffic crashes. The adaptive cruise control (ACC) system is an effective intelligent vehicle active safety system for avoiding certain types of collisions. This study aimed to assess the safety benefits of ACC in China, including the potential maximum impact and realistic impact.
Methods: This study applies a national-level safety impact evaluation model to assess the safety benefits of ACC in China, including the potential maximum impact and realistic impact. Road traffic fatality and severe injury trends in China, proportion of different collision types in China, effectiveness of collision avoidance, and market penetration rate of ACC are considered in the potential maximum impact scenario. Furthermore, the ACC activation rate and the technology's technical limitations, including its effectiveness in different weather, light, speed, and road conditions, are discussed in the realistic scenario.
Results: With a 100% market penetration rate, fatalities could be reduced by 5.48%, and injuries could be reduced by 4.91%. With a large increase in market penetration rate of ACC in the coming future, the reductions in fatalities and severe injuries are 324-957 and 1,035-2,737 in 2025 and 531-1,579 and 1,604-4,242 in 2030. Considering ACC's activation rate and its 4 main limitations, the adjusted realistic result is approximately one-third of the potential maximum result.
Conclusions: The result clearly shows that the ACC system can improve road traffic safety in China. Technical limitations have a great impact on ACC's safety benefits. Of all of the limiting factors, the turn-on rate provides the most room for improvement, and improving the suitability of the ACC system on curved and sloped roads provides the smallest effect.
Keywords: Safety impact; adaptive cruise control (ACC); fatality reduction; injury reduction; intelligent connected vehicles.