This report documents analytical research to determine optimum vehicle lighting parameters for effectiveness in fog. An extensive literature review was conducted, with a major output the definition of Fog Driving Scenarios that characterize conditions associated with driver problems in fog. A computer simulation of nighttime and daytime fog visibility was developed to assess front- and rear-facing vehicle lamp design and mounting. Results of the computer simulation showed that (1) Front fog lamps enhance positional comfort-related visual cues more so than situational safety-related visual cues, (2) Rear lamps provided the greatest potential for visibility enhancement in fog, (3) Daytime fog is not amenable to visibility improvement, (4) The optimum vehicle lighting system for nighttime fog consists of front fog lamps, low-beam headlamps, and relatively high-intensity supplemental rear fog lamps. Results are interpreted against visibility criteria for safe driving speed. Detailed recommendations for optimum parametric lamp design and mounting variables are presented.