In 2016, there were approximately 3.5 accidents where the driver was impaired by alcohol, for every 1 accident where a driver was impaired by drugs.
Yn 2016, roedd tua 3.5 o ddamweiniau lle mae'r gyrrwr yn dan ddylanwad alcohol, ar gyfer pob 1 damwain lle mae gyrrwr yn amharu ar gyffuriau.