A section of the diversion route, the A458 at Nant y Dugoed, has traffic signals in place following a wall collapse, but this is not expected to add significantly to journey times.
Mae gan ran o lwybr y dargyfeirio, yr A458 yn Nant y Dugoed, signalau traffig ar waith yn dilyn cwymp y wal, ond does dim disgwyl i hyn ychwanegu'n sylweddol at amseroedd teithio.