Roadway side slopes should be as flat as practical. Side slopes of 1V:4H or flatter are considered traversable and recoverable. Slopes of 1V:3H are traversable, but are not recoverable. Slopes steeper than 1V:3H are neither traversable nor recoverable. On new construction, 1V:6H or flatter side slopes are desirable.
In some cases, it may not be practical to flatten the entire roadway side slope. In these cases, spot improvements can still improve roadway safety. Consider flattening steep slopes in the following locations: outside of curves, along approaches to intersections, access points and median crossovers, and around bridge piers and drainage culverts. When a nonrecoverable side slope inside the clear zone cannot be flattened, consider installing an appropriate barrier system, such as a guardrail.