The stripes on a highway barricade are not arbitrary. They actually provide directional information. When placed correctly, the stripes on a barricade point down and in the direction of safe passage. In the example above, the barricade is telling you to pass on the left side of the obstacle.

Yellow and black (or other colors) object signs work the same way. You'll see these most often on bridge railings and piers, or traffic islands. Again, the downward slope of the arrows will indicate the side to pass on, and the chevron will tell you that you need to go on either side of the obstacle.