Sorry Nick I am having problems with your answers?
As I said in my previous post I called them roads because Ontario has many side roads that look similar white lines which are part of the scenery files you explained.
So now we have a problem with the white lines that are part of the scenery tiles? Hard to ignore if you are flying over them.
I have checked New York, Ohio, Michigan and Quebec and found no such white lines no matter in what season. They are harder to see in the winter because the scenery is white.
That leads me to believe only the texture used by Orbx in Ontario is the cause of this problem.
I further checked on my older computer which has no Orbx scenery only default Prepar3D and there are no whites lines in Ontario.
So I am lost for words unless you are asking me to except the white lines?
NineMile