It accounts for the highest proportion of all A Trunk roads (27.3%), B and C roads (21.1%) and minor surfaced roads (12.2%), resulting in an overall 15.8% of the total road length of Wales.
Ym Mhowys y mae'r gyfran uchaf o Gefnffyrdd A (27.3%), ffyrdd dosbarth B ac C (21.1%) ac is-ffyrdd ag wyneb caled (12.2%), sy'n cyfateb i 15.8% o holl ffyrdd Cymru o ran eu hyd.