When investigating dynamics of a driver-vehicle system, isolation betw
een driver dynamics and vehicle dynamics becomes important, because in
teraction between them exists in the closed-loop system. The subject o
f this study is to examine effectiveness of AR-method by which each dy
namics can be identified. The AR-method applied to lane changes, usual
ly having rather short duration data, provides usefullness for the iso
lation. This method well reflects variation of subject drivers in iden
tified results, and time series data recoverd by identified VAR-model
is consistent with field data.