While most people have been complying with the reduced speed limit the National Police Chiefs Council (NPCC) identified that there are still people driving at higher speeds.
Er bod y rhan fwyaf o bobl wedi cydymffurfio â'r terfyn cyflymder is mae Cyngor Cenedlaethol Penaethiaid yr Heddlu (NPCC) wedi nodi bod pobl yn dal i yrru ar gyflymder uwch.