Friction needed so car does not spin out? how do you do this?

[nfg5]

An engineer must design a curved exit ramp for a highway in such a way that a car, exiting at the posted speed limit of 13.41 m/s (30 mi/hr), does not depend on friction to round the curve without skidding. The radius of the curve is 213.0 m. At what angle with respect to the horizontal must the curve be banked (in degrees)?

 

[Kurdt]

What have you tried?