摘要:The road transport system has been developed at the urban and interurban level creating appropriate networks in order to service traffic safely and efficiently. The increase of urban traffic flows leads directly to a rise of the externalities associated with motorized traffic. One of the major impacts is the atmospheric damage caused by pollutant and greenhouse gas emissions from vehicles contributing to negative atmospheric phenomena, global warming and climate change. Traffic emissions pose a serious threat because although they do not cause large numbers of direct victims, serious consequences may arise in the long term which are both local and universal in character. In the present study the effects of the urban road networks' functional and traffic characteristics on traffic as well as on the produced emissions are investigated along selected road segments in the city of Thessaloniki, Greece. Towards this purpose, the road network was first categorized according to the road characteristics, based on in-situ surveys. Then, traffic volume and composition field measurements were conducted and the collected data were used for the C〇2, CH4, N2O, NOx and PM10 emission calculation due to motorized traffic using the COPERT4 emission estimation model. Finally, the findings are presented, evaluated and associated with the characteristics of each road category.