I had to stop my truck on the M5 motorway for this.

all work done in adobe photoshop CS3 beta

1) opened as a RAW file--new in CS3--and increased vibrance--similar to saturation-- and increased black which makes the image darker

2) used Noise Ninja to clean up some noise that showed up due to step 1

3) used the water drop tool to eliminate some sharpening artifacts from Noise Ninja

4) used curves to darken the darks and lighten the lights