Sam discussed the Welsh Government's new, default 20mph speed limit on BBC Radio Wales with Vaughan Roderick.
Sunday Supplement, BBC Radio Wales: terfynau cyflymder 20mya gyda Vaughan Roderick
Trafododd Sam derfyn cyflymder diofyn newydd Llywodraeth Cymru o 20mya ar BBC Radio Wales gyda Vaughan Roderick.
