I actually like the sunset idea better. You could add a series of ranged light blue radial lights in the cealing of that walkway. That would lighten up the bridge some, but also give it a cold look. And perhaps a couple of "streetlights" on the bridge, lighting up parts of the road. But either way, you should turn down the ambience on the bridge textures. Makes it look kinda washed out.

Rudolf Herczog
Digital Artist
www.rochr.com