The introduction in Russia of the Euro-5 standard and the tightening of rules on emissions of harmful substances has resulted in an overdue improvement in the methods and algorithms of calculation and design of toxicity decreasing systems to enhance the functioning of devices of these systems. Despite widespread methods of simulation and computer modelling for the study and testing of the proposed organizational and technical measures, it is relevant to assess the increase of exhaust recirculation motor units with the help of experimental studies. The purpose of the study is to evaluate emissions of harmful substances of the car exhaust and suggest an experimental device based on the apparatus and methodology for analysis of carbonyl compounds and volatile organic compounds. In assessing of the effectiveness of reducing the toxicity, significant attention is paid to methods of experimental studies. As an indicator of the effectiveness in reducing the toxicity of motor units, the volume of emissions of harmful substances was selected. The choice of the components of the experimental system for the automated processing of the environmental inspection results of motor vehicles was substantiated. These components are: software tools that implement the conduction of the test by a cold start of the engine and chassis dynamometer settings, as well as monitoring the progress of the experiment; interactive systems to transmit information between the posts of ecological police, private persons and legal entities, companies for the maintenance of vehicles.