The influence of the vehicle age on the calculated probability of exceeding the standardised exhaust emission

The article presents the results of investigations of the influence of vehicle age on traffic exhaust emission. The measurements of the test group of 500 different vehicles have been made in accordance with ECE Regulations and the methodology of periodical car inspection. Those measurements provided Information about the level of emission from each vehicle and allowed to identify high polluting vehicles. The percentage of faulty vehicles and the type of faults were estimated. Next, the percentage of high polluting vehicles has been estimated. The results of investigations were compared to the requirements of each model of a given year. The percentage of high polluting vehicles for each model of a given year has been presented. The vehicles have been divided into different exhaust emission legislation classes. The percentage of high polluting vehicles for each exhaust emission legislation class has been elaborated. Next, the relation between exhaust emission and the vehicle age has been made and presented. The pro bability ofexceeding the standardized exhaust emission for each model of a given year of vehicles has been calculated. The calculations included the exhaust emission such as carbon monoxide and hydrocarbons. The likelihood of carbon monoxide and hydrocarbons emission violations have been estimated applying logit analysis. The calculations have been made in two cases, for manufactures and national emission standards. The results of investigations and analysis show that vehicle age plays a significant role in determining exhaust emission test results.