A field trial has been carried out using a set of automatic recording system, Driving Monitoring Recorder (DMR) and Accident Data Recorder (ADR) installed on 20 vehicles in a fleet of cars in Tokyo area, in order to assess the implications in driving behavior and accidents. The 38 subjects, who drive the 20 vehicles were monitored during driving by the DMR for one year. Simultaneously, the data in pre- and post accident were recorded by ADR whenever accidents occurred. ln addition, the drivers were examined by a driving aptitude test.

The data by DMR are analyzed focusing on fluency of occurrence of emergency brake operation and/or rapid start performance as representing driving behavior as a trial. The 23 accident cases including cross accident, rear-end accident, turning accident, are collected by ADR for one year. The accident data are analyzed focusing on environmental condition in pre- accident stage and driving behavior.

Relationships between driving behavior and accident are proposed as results of data analysis. In particular, the accident mechanisms of specific accidents, in which the subject ranked careless driver involved can be explained in terms of driving behavior, which is determined by his cognition and/or judgment when he is facing specific environmental situations. A set of the automatic recording systems offer very clear benefits to study traffic accident mechanism in particular on the manner of driving immediately before accident, and they will provide hitherto unavailable information in the field of road safety.