A system suitable for an automated-vehicle, said system comprising: a lidar-unit suitable to mount on the automated-vehicle , said lidar-unit used to provide a point-cloud descriptive of an area proximate to the automated-vehicle ; and a controller in communication with the lidar-unit , said controller configured to select ground-points from the point-cloud indicative of a travel-surface ; tessellate a portion of the area that corresponds to the travel-surface to define a plurality of cells ; determine an orientation of each cell based on the ground-points within each cell , the orientation being characterized with an angle relative to level or a vector normal to a plane of the cell defined by ground-points of the cell, wherein the orientation of a cell is determined based on a plane defined by ground points of the cell having a height-value less than a height-threshold , or by ground-points that are within a deviation-threshold of the estimated-plane, define a road-model of the travel-surface based on the orientation of the cells ; and operate the automated-vehicle in accordance with the road-model ; wherein the controller is further configured to divide a cell when a height-deviation from a plane of the cell by the ground-points within the cell is greater than the deviation-threshold ; combine adjacent cells when planes of the adjacent cells are parallel within a parallel-threshold ; designate a cell as a finalized-cell when a deviation from the plane of the cell by the ground-points within the cell is not greater than the deviation-threshold and the plane of the cell is not parallel to any plane of an adjacent cell within the parallel-threshold ; and wherein to define the road-model of the travel-surface is based on the orientation of finalized-cells when all cells are characterized as finalized-cells . a lidar-unit suitable to mount on the automated-vehicle , said lidar-unit used to provide a point-cloud descriptive of an area proximate to the automated-vehicle ; and a controller in communication with the lidar-unit , said controller configured to select ground-points from the point-cloud indicative of a travel-surface ; tessellate a portion of the area that corresponds to the travel-surface to define a plurality of cells ; determine an orientation of each cell based on the ground-points within each cell , the orientation being characterized with an angle relative to level or a vector normal to a plane of the cell defined by ground-points of the cell, wherein the orientation of a cell is determined based on a plane defined by ground points of the cell having a height-value less than a height-threshold , or by ground-points that are within a deviation-threshold of the estimated-plane, define a road-model of the travel-surface based on the orientation of the cells ; and operate the automated-vehicle in accordance with the road-model ; wherein the controller is further configured to divide a cell when a height-deviation from a plane of the cell by the ground-points within the cell is greater than the deviation-threshold ; combine adjacent cells when planes of the adjacent cells are parallel within a parallel-threshold ; designate a cell as a finalized-cell when a deviation from the plane of the cell by the ground-points within the cell is not greater than the deviation-threshold and the plane of the cell is not parallel to any plane of an adjacent cell within the parallel-threshold ; and wherein to define the road-model of the travel-surface is based on the orientation of finalized-cells when all cells are characterized as finalized-cells . <EOS>