In a method for determining a course of a traffic lane for a vehicle (10), structures that demarcate a trafficable space are detected in image data from an image acquisition unit (2), and these structures are plotted on a surroundings map (20) that subdivides the surroundings of the vehicle into a two-dimensional grid (20a) of cells (21). The position of the vehicle in the grid of the surroundings map is determined and updated by odometric data. The distance and the direction of the vehicle (10) relative to those cells (21b) of the grid (20a) having structures that demarcate the pavement and/or the traffic lane are determined. Brightness transitions in the image data are detected and are plotted on the cells (21) of the grid (20a). The course of the traffic lane (22) is determined from the cells with the detected brightness transitions.