Research on Detection of Braking Reactions in Emergency Situations

In this research, an investigation was made of detectable indexes and methods of measuring them among a number of candidate physiological responses that precede a driver’s emergency braking action. Evaluation methods that could be used in detecting emergency situations were identified on the basis of the results obtained. Measurements were made of the electrical activity of the frontal muscle, ocular muscle, brachial biceps, femoral rectus and tibial anterior as well as the operation of the accelerator and brake pedals, gripping force on the steering wheel and pressure on the footrest as potential index candidates. In experiments conducted with an actual vehicle on a proving ground course, test subjects wore a face-mounted display in order to reproduce emergency situations involving potential rear-end collisions. Thirty subjects, including ten older drivers, took part in the experiments. The results showed that the tibial anterior was the fastest to show electrical activity among the muscle responses involved in emergency braking. We have started research on a braking system for reducing collision speed, including devices that detect the driver’s reactions. The system judges whether to apply braking force based on the driver’s reactions and operations, in addition to the distance to an object ahead of the vehicle and the characteristic of vehicle deceleration. This enables the system to apply braking force while giving utmost priority to the driver’s intentions.