A motor grader is used to maintain the surface of a gravel road. It can cut out surface irregularities such as washboards, potholes, and ruts to improve driver safety. Washboards and potholes typically form on hills, curves, flat areas and near stop signs where vehicle braking occurs. Traffic and speed impact the frequency and severity of washboards formation.
In order to cut the compacted gravel to a sufficient depth to remove surface irregularities moisture is required. To get adequate moisture for proper compaction and a tight surface, water is frequently applied using tankers with spray bars. Roads are frequently bladed after rain.