Speed Correction Model For Vehicle Emissions And Fuel Consumption Based On VSP Distributions

The rapid development of motorization has brought a rapid increase of energy consumptions. At the same time, the air pollutions caused by the transportation have been worsened. In response to the transportation energy consumption and air pollution problems, China has developed various strategies to reduce vehicle fuel consumption and emissions. In this background, it becomes a key issue to be addressed by transportation agencies on how to quantitatively evaluate the effects of various strategies on energy savings and emission reductions. Traditionally, using the emission model to predict vehicle fuel consumption and emissions for before and after the implementation of respective strategies is an important means in the evaluation of transportation strategies. However, traditional emission models do not adequately consider the influence of transportation strategies on fuel consumption and emissions, and cannot be integrated with transportation models effectively.In this context, the research in this thesis analyzes the relationships between the speed and fuel consumption and emissions, based on massive data collected by using the Portable Emission Measurement Systems (PEMS) and the Global Position System (GPS) devices, and then develops a speed correction model for vehicle emissions and fuel consumption based on Vehicle Specific Power (VSP) distributions. At first, the study calculates and comparatively analyzes the emission rates and fuel consumption rates of each vehicle type (Standard 0, Standardâ… , Standardâ…¡, and Standardâ…¢) based on PEMS data. Then, it uses VSP distributions to describe the driving behavior of different road types (urban expressways, urban major and minor arterials, and urban collectors) in Beijing based on GPS data. Further, the differences of traffic characteristics on different road types are analyzed, and the relationships between the speed and fuel consumption and emissions are developed by using VSP as an intermediate variable. Subsequently, a speed correction model of vehicle emissions and fuel consumption is developed based on VSP distributions of different road types and different vehicle types.Finally, the proposed model is tested by using statistical approaches and real-world PEMS data, and then applied in a real traffic control strategy in Beijing, e.g. traffic control based on the last digit of the license plate number, to examine the performance of such policy in reducing fuel consumption and vehicle emissions. From the test and application results, it demonstrates that the proposed model can be used reasonably and effectively to evaluate the effects of transportation strategies on the energy saving and emission reductions.