Blender file could not show in Unity

I have a problem with importing a blender file to unity…
So…here is the file:
https://drive.google.com/open?id=0BwEwcU-vikBvTk9EcklITVRTeVk
it was a plane that i changed it to a race track with no adding polygons(with ctrl+r)
I just used alt+d that you can see in the blend file…

Ok!I solved it by my self…
It was blender problem…
i made my road with plane and unity didn’t accepted it as a mesh
So it was unity problem two:/