Actually a method cheaper than lasers exists right now. There is a type of paint that is sometimes used to paint lanes and pavement with that is impregnated with a reflective type mateiral similar to Scotch-lite.
It wouldnt work during the day of course, but it would help some.
This idea rocks! But at the same time, a rider can easily say whist riding in the middle of the road for no reason, "but, officer, I was riding in the bike lane..."