Abstract
On-road driving tests are performed to determine the emission of harmful exhaust compounds from vehicles. These primarily include carbon dioxide, nitrogen oxides, and particle number. However, there is a lack of indicators that combine the first three substances that are the most important in assessing the environmental aspects of vehicles. The purpose of this article is to indicate the possibility of assessing emissions in real driving conditions from light-duty and heavy-duty vehicles of different categories. In order to do so, a portable emissions measurement system (PEMS) and an instrument for measuring the particle number were used. The tests were carried out on routes designed to comply with the requirements and regulations laid down in the European Union legislation. On-road emissions of carbon dioxide, nitrogen oxides and particle number have been determined. Factors have been determined as the multiplication of these compounds for each vehicle category in three phases of the test: urban, rural, and motorway. A new way of assessing emissions from vehicles using new factors has been proposed.