That means you have to look in two places, correlate the information and make a deduction. I would prefer a style of line that is immediately recognisable on its own.
Well, there are bidirectional roads with dashed lines in the middle, so you can overtake, but you should obviously not stay in the lane with oncoming traffic for longer than that. I can see how colours can help there, but in Europe the road situation tends to be clear enough that that isn't necessary.