The Maryland State Highway Administration is responsible for the maintenance of roads and highway systems. It operates more than five district offices throughout Maryland that oversee various road construction and maintenance projects. The administration offers litter pick up, ditch cleaning, mowing and snow removal services. The Maryland State Highway Administration also provides maintenance services for pavement markings, traffic signs, railroad crossings, culvers and retaining walls. In addition, it manages a hauling permit unit that issues permits for oversized, overweight and over-dimensional loads. The administration is also responsible for the collection, processing, analysis, summarization and dissemination of highway traffic data. It is a part of the Maryland Department of Transportation and maintains a location in Greenbelt, Md.