problem on track creation?

[VELOCIPEDE]

it's normal this effect on the white line?
(look the yellow -> )

[Aritz]

I think that you have to adjust better your graphic card, advanced controls. Mip mapping maybe, but better wait to an expert on the matter.

[PiBoSo]

it's normal this effect on the white line?

It is normal. It is due to mipmapping.
The best solution is to create a polygons strip dedicated to side lines, using the TRKLINE material.
A workaround is, inside Kart Racing Pro, to go to settings -> graphics and increase anisotropic setting.