Is the Real Driving Emission methodology really representative of the people’s driving behaviour ? Study of the driving patterns in Brussels

More and more cars are circulating on the roads and this significantly impacts the health of the population as well as the air quality. In that sense, norms on the emitted pollutants of vehicles have been set by the European Union. These norms must be respected by all new vehicles which cannot be launched on the market if they do not pass the tests inspecting their emissions. For years, the emissions of the vehicles have been tested exclusively on a dynamometer in a laboratory. However, most of these testing do not reflect the reality since external factors such as traffic, weather, driving dynamics and shifting behaviour are not taken into account. Therefore, real driving cycles are needed because they are more dynamic. To that extent, the Real Driving Emission (RDE) test has been developed over the years and implemented in 2017. The goal of this test is to measure emissions in real time on public roads. Basically, the vehicle is instrumented with portable emissions measurement systems and the main parameters are the average speed, the distance, the maximal speed and the lower and upper dynamic conditions. This work aims at analysing if these conditions are relevant and representative of Brussels drivers behaviour. Therefore, data loggers recording twelve parameters have been developed and installed in the car of 51 Brussels drivers from one to two weeks. Then, the data were sorted and compared to the conditions of the RDE. The results show that Brussels people’s driving behaviour does not match with the requirements of the RDE for the distance and the stop proportion but were acceptable for the dynamic conditions, the maximal speed and the average speed. The influence of external factors which are the fuel type, whether the vehicle is a company car, the category of displacement, of power and of year of construction, the type of gearbox, whether the engine was cold when it started, the time of the week and the time of the day has also been analysed to understand what impacts the most the RDE conditions. Moreover, a preliminary study was conducted in the data outside of Brussels in one vehicle. They have been compared to data from Brussels and they seem to indicate that the location has a strong impact on the parameters studied.