Painted lines on the road can serve as skeuomorphs of cattle grids. The light-dark pattern of lines on pavement resembles a true cattle grid to animals, and by association think they will not be able to cross. Using a virtual cattle grid is initially cheaper than a true cattle grid, but the cost of periodic re-painting may eventually exceed the initial cost of a well-built metal guard. A particular advantage of painted guards is that they are smooth to drive over; in the US, most are found on state or federal highways, rather than private roads.