The article presents and compares the results of exhaust emission tests in conditions of real vehicle traffic with the results obtained during bench tests on a chassis dynamometer in conditions of road traffic simulation. A series of tests were carried out using a mobile exhaust analyzer and a vehicle speed recorder. The research route was designated in the center of a large urban agglomeration. Laboratory tests were designed according to an algorithm approximating the actual driving sections,

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... nd when choosing their order during the test construction, a random factor was introduced. The presented approach reflects the random nature of road traffic while ensuring the representativeness of toxic emissions from the vehicle's exhaust system. The results of measurements of carbon dioxide emission, carbon monoxide, nitrogen oxides and hydrocarbons registered in road and stationary, laboratory emissin tests were compared. Substantial agreement was found between the tests. Difficulties and differences in results due to research problems have also been described.