Grrr. Okay, I never liked VR. Looked at it when it first came out and decided that having VIZ was far better. Uhhh. Dommy2Hotty should be able to help with that one. I think he uses VR.
You could always take your original idea and covert your lines into regions, set a yellow material on the lines region and the road material on the road plane. That's all I can think of.