Md. Code, Transportation § 21–1204

(a) This section does not apply to any log skid, drag, or farm sled while used in agricultural or forestry practices.

(b) A person riding on any bicycle or motor scooter may not attach it or himself to any vehicle on a roadway.

(c) A person riding on any play vehicle may not attach it or himself to any vehicle on a roadway.

(d) A person riding on any coaster may not attach it or himself to any vehicle on a roadway.

(e) A person riding on any skateboard may not attach it or himself to any vehicle on a roadway.

(f) A person riding on any roller skates may not attach them or himself to any vehicle on a roadway.

(g) A person riding on any sled may not attach it or himself to any vehicle on a roadway.

(h) A person riding on any toy vehicle may not attach it or himself to any vehicle on a roadway.