Association between automatic emergency braking and pedestrian and cyclist injury severity in Japan

This cross-sectional study assessed whether automatic emergency braking (AEB) in colliding passenger cars is associated with reduced injury severity among pedestrians and cyclists in road traffic crashes. We used national police-reported data in Japan from 2016 to 2019 on vehicle versus pedestrian and vehicle versus cyclist injury crashes, focusing on six best-selling car models with optional AEB systems. We analyzed the association between AEB presence and injury severity, dichotomized as fatal/serious versus minor/no injury, using multivariable logistic regression, adjusting for potential confounders. Among 4131 pedestrians and 6659 cyclists involved in crashes, AEB was associated with a 20 % decrease in the odds of fatal or serious injuries among pedestrians (adjusted odds ratio: 0.80, 95 % confidence interval [CI]: 0.64-0.996). No significant association was observed for cyclists (adjusted odds ratio: 0.91, 95 % CI: 0.74-1.14). In conclusion, AEB systems may mitigate injury severity even when collisions cannot be avoided, at least for pedestrians in real-world conditions. Future studies should evaluate the effectiveness of newer AEB systems that detect cyclists and explore variations in effectiveness according to driver characteristics.