The Order will temporarily prohibit vehicles and cyclists on lengths of the M4 motorway and A470 trunk road between Coryton and Merthyr Tydfil.
Bydd y Gorchymyn yn gwahardd cerbydau a beicwyr dros dro ar ddarnau o draffordd yr M4 a chefnfffordd yr A470 rhwng Coryton a Merthyr Tudful.