This study was conducted to determine heavy metals i.e. Lead (Pb) and Cadmium (Cd) concentrations in lichen along different roads having varied traffic density and to find impact of the metals on its growth in Miandam valley Swat, Pakistan. Dermatocarpon miniatum species samples were collected from control site, primary, secondary and tertiary roads and were investigated for Pb and Cd concentrations and reduction in chlorophyll contents. The data were analyzed using ANOVA, correlation and regression analysis. Significant (P<0.05) variation in Pb and Cd concentrations in lichens along different roads were found. It was concluded that traffic density was responsible for Pb and Cd accumulation in lichen. Present findings further highlighted that there was significant variation in the chlorophyll content which amplify the heavy metal accumulation and subsequently inhibited growth of lichens.