AutoCad 3D :: Creating Street Surface Model?

I am trying to create a model of a city street surface using Autocad 2013. I think that perhaps the "network" surface command might work. Although the surface of a street looks simple, it is quite complex because of the need to drain the street of water. The corners are particularly difficult because the surface needs to be a continuous smooth curve while at the same time changing the direction of the surface slant.

I have attached a jpg of a model I created in Maya. I can export this to Autocad, but it is not particularly accurate and I need to create the model in Autocad at my job where they do not use Maya.