在環境因素影響下之城市物流路線規劃問題

Abstract

由於全球都市化之趨勢，未來人類活動範圍將主要在城市區域，而貨物運輸為城市區域的主要活動之一，近年來不斷地增長對環境之衝擊使得城市物流興起，其中車輛路線規劃可有效改善城市裡貨物運輸的環境影響。為考慮環境因素影響，模式目標考慮碳排放，並將旅行時間視為依時性以反映城市壅塞之特性，將汙染路線規劃與依時性車輛路線規劃整合，構建在環境因素影響下之城市物流車輛路線規劃模式，並以範例驗證模式，並進行未考慮碳排之情境分析，與碳稅和燃料價格的敏感度分析。 本研究以數學規劃法求解，分析結果顯示：(1)有考慮碳排成本路線的總距離較短，總旅行時間也較少，但路線所需的時間比較久；(2)未考慮碳排的路線總成本、碳排成本與燃料成本皆比有考慮碳排之路線高，而司機成本是有考慮碳排的路線結果較高；(3)司機成本在有考慮或未考慮碳排路線的各項成本中皆為主要成本。敏感度分析結果：碳排成本對於碳稅之敏感度相較其他成本高，但因其佔總成本的比例相當低，因此對總成本影響不大。碳排成本與燃料成本對於燃料價格之敏感度皆比其他成本高，總成本之變化率隨燃料價格之變動成正向關係。本研究構建之模式可同時將速度與載重造成之碳排成本納入成本計算，並適用於城市區域之車輛路線規劃，在總成本最小化目標下，不僅考慮營運成本，也顧及環境衝擊之影響成本。

Due to the global trend of urbanization, human activities will be mainly in urban areas. Freight transportation is one of the main activities in urban areas, and the relating environmental impacts keep growing in the recent years; it results in the rise of city logistics, and vehicle routing planning can be effective in improving the environmental impacts of urban freight transportation. To consider the environmental impacts, the model takes the emission of carbon into account, and uses time-dependent travel time reflecting congestion in urban areas. The research coordinates the pollution-routing problem and time-dependent vehicle routing problem to develop the model of vehicle routing problem of city logistics under the environmental impacts, verifies the model with the example, tests the scenario without considering the emission of carbon and analyzes the sensitivity of carbon tax and fuel price. The research applies nonlinear programming to the model, the results show that (1) the total distance and travel time in the routes considering the emission of carbon are shorter but the total time routes required is longer; (2) the total cost, carbon cost, and fuel cost in the routes without considering the emission of carbon are higher, but the driver cost is less; (3) the driver cost is major cost in both scenarios. The sensitivity analysis finds that carbon cost is more sensitive to the carbon compared to other costs, but not influencing total cost much. Carbon and fuel cost are more sensitive to the fuel price, and the relationship between total cost and fuel price is positive. The model developed can take the carbon cost influenced by speed and load into cost accounting and be applied in vehicle routing in urban areas.