NYSDOT's Highway Design Manual specifies 1 on 12 for curb going the other way, from flush to raised, mostly so snowplows would ride up it rather than slamming into it. This would also apply to the tires & bodywork of errant vehicles.
If pedestrians use the shoulder, use a 1 on 12 max grade to comply with ADA. Otherwise, I am not sure of any requirements other what's needed to provide drainage.
"...students of traffic are beginning to realize the false economy of mechanically controlled traffic, and hand work by trained officers will again prevail." - Wm. Phelps Eno, ca. 1928
"I'm searching for the questions, so my answers will make sense." - Stephen Brust
Given some more thought, make sure to consider clear zone requirements for traffic coming the other way. For moderate to high volume roads, the left side shoulder will be in the clear zone.
"...students of traffic are beginning to realize the false economy of mechanically controlled traffic, and hand work by trained officers will again prevail." - Wm. Phelps Eno, ca. 1928
"I'm searching for the questions, so my answers will make sense." - Stephen Brust
Thanks for the help. I forgot to mention that this is a one way ramp merging into a freeway. Also, the transition will be from a raised shoulder to flush in the direction of traffic (constant width). Basically the curb line is what will be transitioning across the shoulder. My initial thought was that 1:10 may work.
