In this paper we propose a novel fuzzy driver assistant system using the information provided through vehicle communications. In the proposed system every vehicle receives some information such as speed, density and drivers’ violation from the vehicles in its vicinity. Then a fuzzy decision system is propped to evaluate the danger of each neighboring vehicle. Finally the system suggests appropriate actions to improve the safety of the vehicle. Our proposed system also can be used for making line changing maneuvers (such as overtaking, turning to left and turning to right) safer. Results of extensive simulations show that our driver assistant system decreases the number of potential accidents by 60%. Moreover, the number of accidents caused by overtaking, turning to left and turning to right is decreased by 77%, 74% and 82% respectively.