For side ditches, attention to cross-section design can reduce the likelihood of serious injuries during vehicular encroachments.

Ditches with the cross-sectional characteristics defined in are preferred and should especially be sought when the ditch location is within the clear zone requirements. Where conditions dictate, such as insufficient existing ROW to accommodate the desired ditch cross section or where ditches are located outside the clear zone requirements, other ditch configurations may be used. Typically, guardrail is not necessary where the desired ditch cross sections are provided. For additional information on general applications of roadside barriers, see .

Ditches that include retards to control erosion should be avoided inside the clear zone requirements and should be located as far from the travel lanes as practical unless the retardant is a rock filter dam with side slopes of 1V:6H or flatter. Non-traversable catch or stilling basins should also be located outside the clear zone requirements.