Your yellow street lines do look excellent. It's because they have the faded look things have when seen through all the air between a person's eyes and a distant object. Getting close to the same object the observer sees that the colors are bright and clear.
It'd be interesting to know if there's a formula or guideline for determining the amount of fading on an object by calculating the distance. For modelers, I'd envision a cross-reference table of mixture ratio of color to various listed distances. It would be scale-specific. For instance, say there's a N backdrop building that at normal veiwing distance is considered x scale feet away. Then checking the distance against the ratio column gives the white paint/base color mix to the building's colors for the correct amount of distance fading. This would duplicate the same degree as if actually seeing a 1:1 object at a certain full-size distance.
This would apply to weathering, too. The fading effect should be figured on top of the simulated fading the model has applied.
