A method for detecting road lane markings for a motor vehicle in motion with an image recording unit is presented. The image recording unit points to the road in front of the vehicle and in the recorded image data, brightness differences (contrasts) are analysed and/or edges are extracted. Road lane markings are detected by means of their periodic arrangement. For evaluation purposes, the measuring signal of the image recording unit is transformed into another coordinate system, and the auxiliary function thus obtained is tested for periodic structures.