Dangosodd yr ymchwiliadau cychwynnol y gallai terfynau cyflymder o 50 milltir yr awr sicrhau cydymffurfiaeth o fewn y cyfnod byrraf posibl gwnaethom gymryd camau ar unwaith, gan eu cyflwyno yn y 5 lleoliad ym mis Mehefin 2018 er mwyn gwella iechyd y cyhoedd. Gwnaeth adroddiad terfynol yr Arweiniad ar Arfarnu Trafnidiaeth Cymru gadarnhau'r casgliadau cychwynnol a chafodd terfynau cyflymder o 50 milltir yr awr eu pennu fel y mesurau a fyddai'n fwyaf tebygol o sicrhau cydymffurfiaeth o fewn y cyfnod byrraf posibl o amser yng Nghynllun Atodol Llywodraeth Cymru i gyhoeddiad 'UK Air Quality for Tackling Roadside Nitrogen Dioxide Concentrations' a gyhoeddwyd ym mis Tachwedd 2018.
Initial investigations indicated 50 mph speed limits had the potential to achieve compliance in the shortest possible time, we acted immediately, implementing them at each of the 5 sites in June 2018 to improve public health. The final WelTAG report confirmed initial findings and 50 mph speed limits were identified as the measures most likely to achieve compliance in the shortest possible time in the Welsh Government’s Supplemental Plan to the UK Air Quality for Tackling Roadside Nitrogen Dioxide Concentrations, published in November 2018.