Evaluation Of Urban Vehicle Emissions Based On Microscopic Traffic Simulation

Vehicle emission has becoming one of the major sources of air pollutants among most cities in China. It's convenient and effective to evaluate strategies of emissions control and improve the atmospheric environment by combing technologies of ITS with vehicle emission models. To evaluate motor vehicle emissions based on microscopic traffic simulation in urban areas, the main research contents of this thesis are as follows.First, the framework of vehicle emissions evaluation based on microscopic traffic simulation is proposed, including the functional descriptions of the traffic simulation module, simulation API interface module, database module, and motor vehicle emission evaluation module. Meanwhile, the data flow is analyzed according to the overall architecture and component functions.Second, targeting the core components of the proposed vehicle emission evaluation framework and from the perspectives of design approach, entity analysis, and database table design, the database tables and associated fields are designed, considering the Paramics simulation platform, road transportation entities, and emission evaluation parameters. In addition, through configuring and handling the data source and compile environment, the data exchange algorithm and relevant API programs are designed and developed, resulting in the implementation of the emission evaluation database system.Third, the structure and computation mechanism of the selected IVE (International Vehicle Emission) model are investigated. The parameters of the IVE model are analyzed with the sensitivity analysis conducted on the average speed, VSP distribution, hot soak time distribution, temperature, relative humidity, fuel quality, I/M inspection and maintenance system, cumulative travel distance, indicating the impacts on the primary motor vehicle emission factors.Moreover, the automatic microscopic traffic simulation based vehicle emissions computation approach is proposed, including the descriptions of automatic vehicle type match (simulation vehicle type, common urban vehicle type, and IVE vehicle type), simulation model construction and API execution, IVE emission evaluation algorithms (base emission rate, vehicle fleet distribution, VSP Bin distribution, and local urban information adjustment factors), fleet pollutants emission computation, and regional motor vehicle emission computation. In the meantime, the parameters of VSP distribution, fleet distribution, base emission factor, and fleet vehicle type adjustment factor are computed automatically. Therefore, the motor vehicle emissions can be automatically computed based on the microscopic traffic simulation.Finally, the simulation environment is developed through simulation region selection, simulation road network construction, simulation parameter configuration and calibration, and the regional motor vehicle emissions are computed automatically as the empirical investigation. Through comparing with the results generated from the original IVE model, the results from the proposed methods are shown to be comparable, indicating the validity of the proposed computation approach.The proposed automatic coupling computation between the microscopic traffic simulation model and the motor vehicle emission model can achieve the rapid evaluation of urban motor vehicle emissions, promoting the application of ITS techniques in the urban regional motor vehicle emission evaluation with significant theoretical importance and pragmatic value.