This study assessed relationships between traffic accidents and variables of the physical environment. Daily data on traffic accidents over a 4-year period were compared with daily records of barometric pressure and synodic lunar cycle. No significant variations in the number of accidents were found related to barometric height but a significant lunar periodicity was observed for one of the years considered. The number of accidents occurring during the full moon day was lowest; the highest occurred two days before the full moon. Accidents occurred more frequently during crescent moon than during waning moon, but no significant differences were noted when the lunar month was divided into four intervals of new moon, first quarter, full moon, and second quarter.