Platinum (Pt), palladium (Pd), rhodium (Rh) and gold (Au) were investigated along high-ways of Attica, Greece, with varying traffic, like Katehaki, Messoghion, the intersection between Katehaki, Messoghion and Acharnon avenues, and residential roads, like Pindos and Navarinou roads. Platinum ranges between 110 and 960 ppb in dust samples and from 44 to 820 ppb in soils, Pd ranges between 90 and 1300 ppb in dust samples and from 36 to 1100 ppb in soils. The analysis of dust collected from parts of the roadsides closed to water sewerages reached as high as 2070 ppb Pt and 1980 ppb Pd contents. Gold ranges from 14 to 990 ppb Au (average 230) in dust samples and from 27 to 160 ppb Au (average 95) in soil ones. Any relationship between Au and Pt or Pd is not obvious. The significant fraction of the traffic-related emissions, reaching values over 4 ppm (Pt+Pd), suggest that they may be concentrated into local water systems resulting an environmental risk. Palladium was the most abundant PGE in the grasses ranging from 0.6 to 23 ppb (average 6.8 ppb), Pt ranges between 2.3 and 6.6 ppb (average 4.2 ppb) while Rh is < 0.1 ppb. Average values of the Pd/(Pd+Pt+Rh), Pt/(Pd+Pt+Rh) and Rh/Pd/(Pd+Pt+Rh) ratios decrease from 0.62 to 0.33 and 0.05 respectively, suggesting the Pd>Pt>Rh bioavailability order.