Depending on the level of detail you need, you might be able to use two images on a quadrilateral for the line markings - one with solid centre or lane lines, and one without. Place them alternately to follow the road edges.
Or just use 2D rectangle components for the line itself, placed a little above the road surface to avoid X-fighting. Can’t remember if PB3 will allow you to string 2D objects along a path?
Alas, I cannot use a texture for the highway because if the lanes irregularly.
As far as I know there is no possibility to use 2D profiles in PB 3.
Or, I hope I have been missing something.
If not I think I will have to use a 3D profile and erase parts keeping only flat face and fir dashed lines a 3D component to be adjusted afterward to 2D face.
If you select a face for a profile, it becomes 3D.
If you select a single edge, it becomes a face 2D.
If you apply a texture to it, you can create roads and stuff.