While I agree with everyone, your scenes are looking pretty good, I will do my best to be picky about the lighting.
Both scenes have the same shadows, that is very inaccurate. The lighting in both scenes is too flat, I would say mostly due to inaccurate shadows, or the complete lack of shadows in the background buildings. They look like image planes or background images and some PS work could be done to add shadow detail to match the scenes to improve the overall look.
For the night scene, if the sky is that dark I would expect there to be a lot less light in the scene, or a lot less white/grey light anyways. The moon gives off a blueish tinted light which should make the scene feel colder. Under such lights things like the yellow paint on the road should look a lot less yellow and infact a little more green.
The street lights as mentioned by NeoStrider give off orange light, however if you look on the ground or on objects that they light the colour they receive is a much less intense orange as when you look into the bulb. So I might recommend using 2 lights in them, one light to give you the glowing red/orange with a faloff, and then a spot with a less diffused orange/red for the light that is actually emitted onto most objects from the street light.
Don't forget about awesome tools like photoshop, painter, or any other photo editing program. You may find it a lot less time consuming/easier to edit/create the necessary effects in a post production/editing program. A lot of the stuff in the scene now appears to be quite flat and you could manually add your shadows/light. Just something to keep in mind based on the scope of your project.
Cheers,
Alexander