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 .