There where multiple issues found in the urban scene that manifested themselves in a "night" render:
* The streetlight GDBs had corrupted source pointing (normal) vectors.
  The made the sources point more in the +X direction than down (-Z).
* The INT files for the Sodium and Mercury lamps needed to be rescaled
  to produce the correct luminance values.
* The source materials were updated to use the normalized shape (constant
  total power vs. shape) feature.