Research On Urban Taxi’s Air Polluction Calculation Method And Emission Reduction Strategies

As the key component of urban passenger transportation system, the taxi provides the passengers with a 24-hour non-stop, convenient and comfortable service. Taxi vehicles’ frequently start, acceleration and deceleration, as well as the lower speed operating for a long time, which have brought a series of external effects, and damaged the overall environment of the city and people’s physical and mental health. How to reduce the air pollution emissions of the taxi and improve the air environmental quality, which have an important theoretical and practical significance in controlling the urban traffic pollution and easing traffic congestion. This paper took the urban taxi pollution emissions and mitigation strategy as the research object, from the perspective of system engineering, traffic engineering, environmental science and management science to analyze and discuss.Based on the continuous 204 hours taxi GPS data of Shenzhen in April 2011, integrated with the theory of data statistics method, this paper had preprocessed the taxi GPS data. Adopting the statistical distribution of the mean center, median, standard deviation ellipse and standard deviation distance to obtain the taxi driving speed, the average daily traveling distance and vacant traveling distance, taxi passenger demand distribution and the time-space distribution of passengers’ pick-up and drop-off in Shenzhen, which can provide data support for the later research on taxi’s air pollution emissions and mitigation strategies.After getting taxi vehicle’s basic operation data, based on the existing taxi air pollution emission model, this paper established a taxi air pollution emission model with the considering of vacant traveling distance. With the integration of Shenzhen taxi data to quantify the proportion of vacant state in the taxi air pollution emissions. Considering the taxi operating speed, traveling distance and Vehicle Specific Power, this paper had built the urban taxi energy consumption and air pollution emission test method and model, which is one of the key isuues of this paper. This model had used the distribution of VSP as variables of taxi emissions and GPS data; After combining the daily traveling distance of the taxi, which can quantitate Shenzhen taxi vehicles’ total air pollution emissions.In the technique level of taxi air emission reduction, combined with the taxi stop setting method and taxi passengers’ pick-up points spatial-temporal distribution on hot spot, had discussed the setting of taxi stops’ effect of pollution emissions reduction. By comparing the statistical data of one taxi operation company’s before and after using the taking a taxi software, had obtained the taxi operating average traveling distance, empty traveling distance, and in-depth analyze the use of software on the taxi air emission pollution reduction effect. Aiming at the taxi drivers who’s searching for passenger time was longer, had analyzed the taxi drivers’ experience driving paths effect on emission reductions and search time. Then contrasted the three methods’ impact on the taxi air pollution emission.In the management level of taxi air emission reduction, based on the analysis and forecasting the future taxi inventory of Shenzhen, considering the taxi air pollution emission reduction targets, this paper had discussed the taxi update and optimization process without the investment restriction. Then established a taxi update and optimization model under the investment restriction, with the comprehensive consideration of the taxi vehicle’s purchasing cost, subsidies, and emissions, which can provide taxi vehicles’ management optimization scheme for taxi operation companies and government management department.In the policy level of taxi air emission reduction, in order to solve urban traffic congestion and carbon emission issue, on the premise of considering a carbon tax, had established the bi-level optimization model for congestion pricing. The upper level model aimed to minimum the total travel cost of the travelers in the road network, while the lower level model is aimed at the optimal to various traffic flows. Based on the direct search algorithm of the step acceleration method and penalty function method, this paper adopted the Matlab software to solve the model. Example analysis had shown that the reasonable urban passenger transport carbon tax and congestion price can effectively reduce carbon emissions by taxi.This paper had studied the urban taxi vehicles’ environmental and air quality improvement issue, which have a great significance to improve the urban taxi operation efficiency, reduce air pollution emission and improve the air quality, and also can provide reference and basis for the management, operations, and energy conservation and emissions reduction in urban passenger taxi system.