Maryland Transportation Section 22-404.1

      (a)      A person may not display on a motor vehicle the insignia or emblem of any motor vehicle club or similar organization, or of a fire company, unless he is entitled to use the same under the constitution, bylaws, rules, or regulations of the club or organization.

      (b)      A person may not display on a motor vehicle any sign that, in the judgment of the Administration, may tend to create a hazard to safety.