AASHTO's Roadside Design Guide has a lot of information on this subject, with regards to recoverable slopes and roadside obstructions, guardrails, etc. Geotechnical conditions (soil type, rock, etc.) can also govern the slopes you would consider. Without more information you aren't going to get a very detailed answer.
I believe the OP was asking about driving surface (paved) cross-slope, not the embankment/sideslope, which is where the Roadside Design Guide comes in.
Most DOT's have superelevation tables, based on speed and road widths. These would serve as a good starting point to determine maximum allowable cross-slopes.
Thanks everybody.
My case is not to find super elevation on horizontal curve. My road section is straight road.
Do I need to consider anything but drainage for transverse slope. Or 7% slope can cause any safety concern?
Sorry if I have caused any confusion.
AASHTO Exhibit 4-4 from the link IRstuff provided shows a table indicating 1.5-2% for high wind, high traffic areas an 2-6% otherwise. There is considerable additional guidance given for selecting a specific slope.
What you call smoothness is also typical in specifications (1/4" in 10' is in our state DOT spec.) The biggest concern is usually "birdbaths" (spots that would collect a pocket of water (ice)).
