In this paper, an integrated headway adaptation (HA) with collision avoidance (CA) system is proposed to be associated with a human factor aspect for driving assistance. The maneuver in the CA strategy is developed based on the idea that warning or potential crash information generally can be graded such that the driver need not react to a discrete on/off warning. The control law for the HA strategy is designed by using a modified sliding surface to achieve driving comfort requirement and also stability in car-following. To simulate the speed controlling of human drivers, the throttle and brake actuation is directed by the regulation control which is designed based on a human reasoning approach. A description of an experimental vehicle and real traffic testing in highways and urban-like tracks shows the potential and validness of the integrated system.