The transport sector has an important role to play in the effort to avert the dangerous effects of climate change because it heavily depends on fossil fuels. Currently, most transport related emissions are concentrated in urban areas which account for the largest share of on-road transport energy consumption. It is estimated that transport sources in developing countries contribute about 4% of the global fossil carbon dioxide versus 18% by industrialized countries. The cost of urban air pollution is estimated to be 2% of GDP in developed countries and more than 5% in developing countries. Adama is one of the old cities in Ethiopia and it is at a distance of 100 km from capital city of Addis Ababa, Ethiopia. Most of heavy duty truck vehicles in the country are across Adama because of it is corridor of import and export. With an annual vehicle registration and a population growth of over the year, the number of trucks continues to grow exponentially in Adama City. With the increasing urban population and there is an increasing demand for transportation vehicles in Adama necessitating increased air pollution around the city. Most of the minibus vehicles used in Adama has very low energy efficiencies, mainly because they are imported into the country when quite old. The general objective of this study is to examine the pollution caused by gasoline and diesel fueled vehicles in Adama. The measured vehicle emissions have been analyzed in detail. It found that emissions like CO, NOx, HC, PM and CO2 levels are higher than worldwide standards for human and environmental health. The findings indicate the level of pollution is high and will continue to grow if left unabated. Tailpipe emission findings estimated the highest level of NOx emissions at 3.44 g/km, HC emissions at 6.53 g/km, CO at 13.9 g/km, PM2.5 at 1.3 g/km and 35.96 g/km of CO2. These amounts of emission exceed the proposed draft NEMA ambient air quality emission data and the World Bank ambient air quality guidelines. This implies that persons exposed to these emissions on a daily basis are likely to develop health complications over time as the concentration levels increase. Several mitigation methods can be applied to reduce the emission level such as reduce consumption of fossil fuels and increase efficiency in transport usage of energy. This study confirms that exhaust gases from vehicles pollute Adama’s air, and that improperly maintained vehicles contribute significantly to this pollution. It is recommended that a comprehensive motor vehicle pollution control program be designed to implement the proposed NEMA vehicle emission standards. Establishment of an integrated transport system should be made priority to 

enable the decongestion of Adama city.