There is no common width that applies to all PRoWs unless it is recorded in the Definitive Statement, each route needs to be considered individually.
Nid oes lled cyffredin sy'n berthnasol i bob hawl dramwy gyhoeddus oni bai bod hynny wedi'i gofnodi yn y Datganiad Diffiniol, ac mae angen ystyried pob llwybr yn unigol.