Mae'r terfynau cyflymder ar waith yn y lleoliadau canlynol:yr A494 yng Nglannau Dyfrdwyyr A483 ar bwys Wrecsamyr M4 rhwng Cyffyrdd 41 a 42 ym Mhort Talbotyr M4 rhwng Cyffyrdd 25 a 26 yng Nghasnewyddyr A470 rhwng Glan-bad a Phontypridd.
The speed limits are in place at the following locations:A494 at DeesideA483 near WrexhamM4 between junctions 41 and 42, Port TalbotM4 between junctions 25 and 26, NewportA470 between Upper Boat and Pontypridd.