● The profile should be smooth with gradual changes consistent with the type of
facility and the character of the surrounding terrain.
● A “roller-coaster” or “hidden dip” profile should be avoided.
● Undulating grade lines involving substantial lengths of steeper grades should be
appraised for their effect on traffic operation, since they may encourage excessive
truck speeds.
● Broken-back grade lines (two vertical curves—a pair of either crest curves or sag
curves—separated by a short tangent grade) should generally be avoided.
● Special attention should be given to drainage on curbed roadways where vertical
curves have a K value of 167 or greater, since these areas are very flat.
● It is preferable to avoid long, sustained grades by breaking them into shorter intervals
with steeper grades at the bottom.