Abstract: Based on the analysis of drivers overtaking process characteristic and combined with the overtaking experiment,the drivers'gap acceptance behaviors at the same directional lane are studied.The experiment data and the result indictates that the gap acceptance behavior can be described by binary choice model-Logit model.The calculntion methods of how to determine the critical head space gap and critical head time gap are also put forward,and the connection between the critical lead time tap,the critical head space gap and the velocity is anasyzed.At last,the conclusion that the drivers are more sensitive to head space change than to head time change in the overtaking process is obtained.