Longitudinal gutter slopes should usually be not less than 0.3% for curbed pavements, although this minimum may be difficult to maintain in some locations. In such situations, a rolling (sawtooth) gutter profile may be necessary. The roadway designer may need to warp the longitudinal slope to achieve a rolling gutter profile as shown in Figure 10-1. Extremely long sag-vertical curves in the curb and gutter profile are discouraged because they incorporate relatively long, flat grades at the sag which tend to distribute runoff across the roadway surface instead of concentrating flow within a manageable area.