Statistical analysis on real kinematic urban driving cycles by preliminary use of VSP variable

Still today true level emissions assess coming from transport activities is a key element in the evaluation of any transport policy both in Europe and the world context. In the next years, further reducing vehicle emissions will be one of the most important development of sustainable mobility. Increasingly stringent emission regulations require continuous optimization that must be validated in new test cycles. Therefore, several aspects related to the assessment of vehicle pollutant emissions are still the subject of research studies. Some preliminary considerations will be developed trying to evaluate how it is possible to integrate the Vehicle Specific Power (VSP) in a statistical approach of vehicle kinematic. This kind of activity globally aims at valuation of traffic situation and emissions in real use. Driving data and emissions are acquired during an experimental campaign through four instrumented vehicles by a portable emissions measurement system (PEMS) for the simultaneous acquisition of emissions, kinematic variables and global positioning system (GPS) data. Statistical analysis results are relative to Principal Component Analysis (PCA) and Cluster Analysis (CA) performed on kinematic data to better characterize road tests and driving behaviour. In this paper, we study the way to integrate VSP index in a statistical approach, since this index is widely recognized in the literature to synthesize the contribution of kinematics along with road gradient.