Unfortunately, far more highway bridges in the United States are "substandard" than are able to be repaired. A common sign of bridge deck wear is loss of skid resistance, which often becomes evident when water collects on the bridge deck. Bridge deck designers usually try to minimize water accumulation by establishing a cross slope with drainage channels and by deck surface texturing. A common method of texturing is transverse tining with a metal rake while concrete is still plastic. Although this method can produce grooves deep enough for a high-friction surface, the grooves are nonuniform and limited in depth.