Mae'n dda gen i ddweud bod allyriadau deuocsid nitrogen (NO2) wedi gostwng ym mhob un o'r 5 lle ar draffyrdd a chefnffyrdd Cymru lle cafodd cyfyngiadau cyflymder o 50mya eu cyflwyno, gan gynnwys ar yr A494 yng Nglannau Dyfrdwy a'r A483 ger Wrecsam. Hefyd, yn sgil treialu camerâu cyflymder cyfartalog, mae nifer y gwrthdrawiadau wedi gostwng ar yr A55 yn Gallt Rhuallt.
I was pleased to see a reduction in emissions of nitrogen dioxide (NO2) at all 5 locations on the motorway and trunk road network in Wales where 50mph speed limits were introduced, including the A494 at Deeside and A483 near Wrexham.  The trialling of average speed cameras has also meant fewer collisions on the A55 at Rhuallt Hill.