Method for estimating road lane geometry, the method comprising: providing a camera lane estimation comprising at least one camera-estimated lane segment, based on camera detection of road markings; providing a leading vehicle lane estimation comprising at least one leading-vehicle-estimated lane segment, based on traces of at least one leading vehicle; and stitching the at least one camera-estimated lane segment and the at least one leading-vehicle-estimated lane segment to obtain the estimated road lane geometry, wherein the at least one camera-estimated lane segment and the at least one leading-vehicle-estimated lane segment are each given by their left edge (7; 12) and their right edge (8; 13) and the left edges (7; 12) and rights edges (8; 13) are given, in particular, as a list of two-dimensional points, wherein the at least one camera-estimated lane segment and/or the at least one leading-vehicle-estimated lane segment are extrapolated, in particular until they reach and/or overlap with an adjacent lane segment, wherein adjacent lane segments are stitched together if the overlap of the adjacent lane segments in a direction perpendicular to a driving direction of the lane is greater than 50 %, preferably greater than 65 %, more preferably greater than 80 %, wherein a stitching quality measure is assigned to each of the stitches of the adjacent lane segments, in particular based on the overlap of the adjacent lane segments in a direction perpendicular to the driving direction of the lane, wherein an extra road lane is added if the overlap of a leading-vehicle-estimated lane segment with other lane segments in a direction perpendicular to the driving direction of the lane is less than 15 %, preferably less than 5 %, more preferably 0 %. providing a camera lane estimation comprising at least one camera-estimated lane segment, based on camera detection of road markings; providing a leading vehicle lane estimation comprising at least one leading-vehicle-estimated lane segment, based on traces of at least one leading vehicle; and stitching the at least one camera-estimated lane segment and the at least one leading-vehicle-estimated lane segment to obtain the estimated road lane geometry, wherein the at least one camera-estimated lane segment and the at least one leading-vehicle-estimated lane segment are each given by their left edge (7; 12) and their right edge (8; 13) and the left edges (7; 12) and rights edges (8; 13) are given, in particular, as a list of two-dimensional points, wherein the at least one camera-estimated lane segment and/or the at least one leading-vehicle-estimated lane segment are extrapolated, in particular until they reach and/or overlap with an adjacent lane segment, wherein adjacent lane segments are stitched together if the overlap of the adjacent lane segments in a direction perpendicular to a driving direction of the lane is greater than 50 %, preferably greater than 65 %, more preferably greater than 80 %, wherein a stitching quality measure is assigned to each of the stitches of the adjacent lane segments, in particular based on the overlap of the adjacent lane segments in a direction perpendicular to the driving direction of the lane, wherein an extra road lane is added if the overlap of a leading-vehicle-estimated lane segment with other lane segments in a direction perpendicular to the driving direction of the lane is less than 15 %, preferably less than 5 %, more preferably 0 %.