My state agency commonly uses gutters with a 4% cross slope. The maximum superelevation rate is 7%. The gutter slope stays at 4% in this situation. Spread does not compute in this scenario because "A depressed gutter must have a Gutter Cross Slope that is equal to, or steeper than, Road Cross Slope". This should not be the case. Any spread section should be computable using HEC-22 methodologies.