プロトコル分析による自動車運転時の判断過程の分析 連転支援装置の有無と運転経験による運転方略·操作の差異

摘要

Eight subjects (3 novice drivers and 5 experienced drivers) participated in this experimental driving on an expressway. A car equipped with an Adaptive Cruise Control (ACC) system was used. When there was no car in front, ACC kept the vehicle speed selected by the driver. When ACC detected a car ahead, it adjusted the speed to keep safe distance from the car. It was anticipated that ACC would contribute to the reduction of drivers' fatigue. In either condition of the use or non-use of ACC, the subject was asked to think aloud about driving.Resulting verbal protocols were analyzed to determine their decision-making process as to the acceleration of the car. And the effect of the differences in driving experiences and that of the use or non-use of ACC were examined. Moreover, the relations among the decision-making process and driving parameters (speed,distance to the car ahead, degree of throttling, etc.) were determined.According to the time-series analysis of the protocols,novice drivers could not relate the obtained information (speed of the car ahead,distance to the car ahead,vehicle speed) systematically. In a condition without the use of ACC,both novice and experienced drivers had produced more protocols than in the ACC condition. In other words,more interactions with the environment occurred. According to the cross-correlation analysis between the degree of throttling and other parameters (distance to the car ahead, vehicle speed,relative speed,time allowance),it was suggested that novice drivers decided to accelerate mainly based on "a distance to the car ahead".It was further demonstrated that the features of actual objective parameters corresponded to the sequential patterns of the protocols.