Legislation to lower the default national speed limit on restricted roads from 30 mph to 20 mph was made by the Welsh Ministers on the 13 July 2022.
Cafodd deddfwriaeth i ostwng y terfyn cyflymder cenedlaethol diofyn ar ffyrdd cyfyngedig o 30 mya i 20 mya ei gwneud gan Weinidogion Cymru ar 13 Gorffennaf 2022.