Yellow lines are used to separate traffic moving in opposite directions, and white lines are used to separate traffic moving in the same direction, and on the shoulders of paved roads. On one-directional roads, a yellow line appears on the left shoulder, and a white line on the right shoulder. Passing rules are denoted by dashed lines as in the United States. In Ontario, it is legal to cross a single or double solid yellow line along a straight road and the vehicle is not within 30 metres of a bridge or railway crossing.