Highways England (formerly the Highways Agency) has implemented an annual correlation trial for SCRIM survey vehicles, which are currently carried out by TRL.
Mae Trafnidiaeth Cymru (TrC) wedi trafod â'r Ganolfan Genedlaethol ar gyfer Ymchwil Cymdeithasol (NatCen) i gyflwyno'r arolwg dros y tair blynedd nesaf.