混合車流污染排放與擴散模式之建構

Abstract

道路交通運輸為能源消耗、空氣污染以及溫室氣體排放的主要產生者，因此透過一個可有效模擬因交通運行所造成的排放與路側區域污染影響之模式，並以此作為即時交控策略之參考依據為一相當重要之課題。為符合國內之汽機車混合交通特性，本研究希望藉由混合車流模式模擬道路車流運行行為以推估移動源排放量，並藉由空氣擴散推估模式分析在各種不同交控策略情境下之污染物擴散情形。因此本研究之目的主要在於進行混合車流格位傳遞模式(mixed traffic cell transmission models, MCTM)與污染排放、高斯擴散模式之整合，提供一動態道路交通污染濃度推估模式。 本研究將探討一號誌化交叉路口，透過不同的號誌時制控制方案，進行區域內一氧化碳(CO)之排放與不同距離下污染物擴散影響與比較。透過本研究之設計情境結果顯示，污染濃度之推估結果會受到排放源強度、風速、受體與排放源點之距離等相關之環境因素影響，然而隨著距離的增加，平均污染濃度會有逐漸下降的趨勢。另外，延滯的增加雖然對於污染排放也明顯增加的情況，但對路口的污染濃度則沒有隨之增加。

Since road traffic is one of major sources of energy consumption, air pollution and greenhouse gases emission, a model which can efficiently simulate the emission and dispersion of road traffic and serve as the platform to implement a real-time traffic control under the constraint of emission concentration in certain environment sensitive areas along the roadway is imperial. To acknowledge the prevailing of mixed traffic consisting of cars and motorcycles on most of urban streets in Taiwan, this study develops the emission and dispersion model based on our previously proposed and validated mixed traffic cell-transmission model (MCTM). Additionally, the emission coefficients of various types of motor vehicles and the Gaussian puff dispersion model are integrated into the MCTM model to simulate the dynamic emission concentration along the roadway. To investigate the applicability of the proposed model, a signalized intersection under various traffic conditions and signal timing plans are simulated and compared. Taking one of pollutants, carbon monoxide (CO), as example, dynamic CO concentrations of a total of 10 spots at different distances from the intersections are analyzed and compared. Results show that the CO concentration decreases as the distance from the intersection increases. Moreover, it is interesting to note that the total CO emissions will increase as the intersection delay increases, but the CO concentration does not remarkably increase.