The consumption of fossil fuels by on-road vehicles is a main source of air pollution specifically greenhouse gases (GHGs) worldwide. The construction industry, due to the use of a large number of heavy-duty equipment including haulage trucks, contributes to a significant amount of fuel consumption and consequent emissions production. Due to increasing number of vehicles on the road, traffic condition is becoming one of the main variables having a considerable impact on the fuel use and emissions of such vehicles. There is a lack of comprehensive studies in construction field quantifying the effect of road traffic on fuel use and emissions of construction equipment. This research aims to model the impact of traffic conditions on fuel use and emissions of on-road construction vehicles. The research framework is first developed to present the methodology of data collection and analysis, and then introduce the fuel use and emissions models applied in predicting the effect of traffic conditions. Three variables of driving speed, idling time and equipment stop are identified as representatives of traffic conditions, and their impacts on fuel use and emissions are quantified through conducting statistical analyses on collected field data. The achieved results found that by having more effective traffic management and planning, the fuel cost and consequent emissions can be reduced up to 9% due to the decreasing idling time of equipment. It is also indicated that by lowering the number of equipment stops, up to 0.66 l/100kW fuel is saved and up to 1.7 kg/100kW CO2 is emitted less per each stop.