Dusty! Did you figure out what game, or should I say server I'm using these for?
If you didn't I'll give you a hint: look at the manhole covers : )
I'd honestly ditch the dithering on the street lines. It looks very dirty and messy, and honestly looks more like someone was fiddling with the spray tool. I don't think it reflects what you're going for very well at all.
Really good advice, your edit helped a lot.
colors need to be worked with as well. I see you're working with pure gray shades, and it might help to add just a hint of color to your colors, even the road(I gave it a purple shade, as I believe roads are mostly seen as such), to give it a little life.
When I set out to make these tiles, I thought exactly the same thing. They are gray now because the powers at be told me: "Sidewalks aren't cream colored, they're gray god damn it, fix it.
Damn, I wish I had another GFXer to work with on this. Sales told me he asked for your help and you declined? Any chance you'd change your mind?
anyways thanks for the post, extremely helpful.
-Luke