The Commission may establish grades for all roads in the regional district. In Montgomery County, all road grades shall be established in accordance with local law. In Prince George’s County, the Department of Public Works and Transportation shall establish road grades. Permanent road grading may not occur until a road grade has been established by: the Commission in Montgomery County; or the Department of Public Works and Transportation in Prince George’s County. Unauthorized permanent road grading is a misdemeanor and is punishable under Title 27 of this article.