An object detection system includes a lidar-unit and a controller. The controller defines an occupancy-grid that segregates the field-of-view into columns, determine a first-occupancy-status of a column based on first-cloud-points detected by the lidar-unit in the column by a first-scan, determine a second-occupancy-status of the column based second-cloud-points detected in the column by a second-scan, determine a first-number of the first-cloud-points and a second-number of the second-cloud-points, and determine a dynamic-status of the column only if the column is classified as occupied by either the first-occupancy-status or the second-occupancy-status. The dynamic-status of the column is determined to be moving when a count-difference between the first-number and the second-number is greater than a difference-threshold, and the dynamic-status of the column is determined to be static when the count-difference is not greater than the difference-threshold and a registration-factor that aligns the first-cloud-points to the second-cloud-points is less than a registration-threshold.