Got asked this question this week and thought I would share the concept.
So within Civil 3D we have the capability of using an ‘A’ value.
In the UK we use RL value which is very similar expression
Within the Civil 3D country kit for UK and Ireland I have had a calculation table in there for some years, probably a little hidden.
Take a look here at this updated attachment (note this is updated to the as installed version as the L value on the Q 0.6 section was incorrect, but the 'A' value was correct. (Thanks to Pawel Zawadzki for a good spot)
Here a quick video of it in action