You may enter a yellow box junction when your exit is clear and there is enough space on the other side of the junction for your vehicle to clear the box completely without stopping.
Cewch chi fynd i mewn i gyffordd sgwâr melyn pan fydd eich allanfa yn glir a phan fydd digon o le ar ochr arall y gyffordd i’ch cerbyd ddod allan o’r blwch yn llwyr heb stopio.