The present invention relates to a method and apparatus for determining traffic condition comprising the steps of determining periodically a position data of a host vehicle 1, wherein the position data includes a time stamp, position, velocity and driving direction of the host vehicle 1, receiving periodically position data of at least an other vehicle 2, 3, 4, wherein the position data includes a time stamp, position, velocity and driving direction of the other vehicle 2, 3, 4, storing the position data of the host vehicle 1 and the position data of at least the other vehicle 2, 3, 4, calculating a relative position data, wherein the relative position data includes relative velocity and relative driving direction between the host vehicle 1 and the other vehicle 2, 3, 4, and judging a traffic condition based on the position data of the host vehicle 1, the position data of the other vehicle 2, 3, 4 and the relative position data.