In order to debug the visual artifact you are seeing (the blurring at distance) we would need to see how you are adding the landscape, road and road lines to the scene. I am assuming you are achieving a road animation effect using a material animation but we need to see that mechanic too.

If your road or lines are separate 3D shapes with semi transparent materials then the order they are added to the scene will determine some transparency effects. Just guessing here. Need much more info.