Environmental physical activity (EPA) is considered as one of main regulators of human homeostasis. Evidence is growing that components of this activity through the "human factor" (i.e., changing human physiological and psychological status) can affect the dynamics of traffic accidents (TA)-the modern life epidemic. This paper presents results of studies conducted in order to reveal the potential influence of EPA [solar (SA), geomagnetic (GMA) and cosmic ray (CRA) activities] on the number of TA and related casualties in the years of the maximum and declining phase of SA cycle 23 (2000-2005). We selected the 7,160 most severe TA and their related 7,558 deaths and 1,647 severe injuries, registered in the Grand Baku Area (Azerbaijan, middle latitudes), for analysis. A significant increase of TA and victims was observed during the whole year and also during the last months of the year. The monthly numbers of TA and victims were inversely related to SA (probability p = 0.0002), and non-significantly to background GMA, but were significantly affected by major geomagnetic disturbances and storms. A strong correlation between CRA variations (cosmic ray intensity measured by ground-based neutron monitors on the Earth's surface) and the number of TA (p = 0.001) has been observed. It was found that the number of TA which occur within a month depends significantly on the particular month of the year, the CRA, and the SA levels (inverse correlation). The increase of the number of TA is also significantly linked to geomagnetic storms, but not to steady GMA. These effects can be related to changes in human functional and behavioral markers provoked by EPA influences.