Thanks mjfarrell.. Sory for my poor English.
Yes I want to define same slope for both sides.
But I have no constant superelevation value. Because right lane is targetted to a vertical featureline.
So right side's slope is changing during its aligment. Right lane slope is changing from +2% to -2%.
Also Left lane should change from -2 to +2.
For instance:
at a 0+100 station if right lane slope is +1.23%, left lane slope must be -1.23%.
at a 0+110 station if right lane slope is +1.17%, left lane slope must be -1.17%.
at a 0+120 station if right lane slope is +1.10%, left lane slope must be -1.10%. etc..
Right lane changing becouse of vertical definition. Bu I didnt define left side's slope depending on right side's elevation .