3d Architectural Visualization of:

Rendering Rule #18

Asphalt (roads) should generally have a small amount of reflection. Partly because they are subtly reflective but more importantly because it transforms that large boring dark expanse into something more interesting. It also adds depth to the 3d rendering. If they'd be there in the real world, add road striping too...but not so much that they become a focal point. You're just trying to break up the monotonous space.