Driving maneuvers in car following are affected by not only road structure and traffic characteristics，but also drivers' cognition to visual information. The purpose of this paper is to discuss the relation between drivers' cognition and driving maneuvers. In order to accomplish this purposes driving maneuvers are observed by a video recorder set up in a car and a driver is interviewed about the degree of his recognized velocity and traffic density on road. The obtained new knowledge is summarized as follow. Driving maneuver is affected by road and traffic characteristics under congested traffic condition，but under free flow condition driving maneuver is affected by drivers' cognition to visual information such as velocity and traffic density.