The speed limit in each direction between Junction 14 and Junction 17 is 70 mph, apart from a 30 mph limit in the eastbound direction around Penmaenbach headland.
Y terfyn cyflymder i'r ddau gyfeiriad rhwng Cyffordd 14 a Chyffordd 17 yw 70mya, ar wahân i derfyn cyflymder o 30mya tua'r dwyrain o gwmpas pentir Penmaenbach.