Finally got the turnaround for the pedestrian zone sign finished and posted on YouTube:
For the pole and brackets holding the sign I applied a galvanized metal texture to the meshes and created a bump map on the same texture to give them a more authentic feel. The signs themselves just have specularity and reflectivity maps applied, breaking up the reflection of the surface a bit and mimicing the weathering that such signs would encounter without altering the surface of the signs as a bump map would.
Researching information for the graffiti on the back of the middle sign, I came across the concept of Stasi 2.0 (English here), a current civil rights hot topic in Germany regarding the use of current and emerging technology for preemptive security measures. I like the stencil on the back of the sign, however there appears to have been some stretching when I unwrapped the meshes that is distorting the graffiti somewhat. Perhaps also add a few stickers as well? In any case, here is an improved render of the sign:
Looks a lot better. Now I'll need to think of some other objects that can be found in the pedestrian zone and model them next.