It takes longer to stop and if there is a collision, it is more severe, causing greater injury to vehicle occupants and any other road user they hit.
Mae’n cymryd mwy o amser i stopio ac os bydd gwrthdrawiad, mae hwnnw’n fwy difrifol, gan achosi mwy o niwed i bobl mewn cerbydau ac unrhyw ddefnyddiwr ffordd arall sy’n cael ei daro.