To claim compensation under Part I of the Act, a qualifying interest in the land must have been acquired before the alterations were completed and first open to public traffic.
I hawlio iawndal o dan Ran I o'r Ddeddf, rhaid bod buddiant cymhwyso yn y tir wedi'i gaffael cyn i'r newidiadau gael eu cwblhau a chyn iddo fod yn agored i draffig cyhoeddus am y tro cyntaf.