If 20 mph zones were retained for use in such rare circumstances, it would be difficult to expect the public to understand them and how they differed from the general 20 mph limit.
Pe bai parthau 20 mya yn cael eu cadw i’w defnyddio mewn amgylchiadau mor brin, byddai’n anodd disgwyl i’r cyhoedd eu deall a sut yr oeddent yn wahanol i’r terfyn 20 mya cyffredinol.