以工作負荷與轉彎合適性為基準之垃圾車巡迴路線規劃

Abstract

垃圾清運路線規劃是廢棄物管理及目前正試辦之清運發營化計畫中重要的一環。然而傳統上使用的經驗法則不易迅速地針對不同變化及狀況改變原有規劃，因此需要尋找一個工具輔助規劃。再加上以往路線規劃多只專注於成本的削減，而忽略了各車工作負荷分配的公平性。此外，清運行車時轉變的安全性與便利性亦對垃圾收集甚為重要，本研究因而建立一個能在合理運算時間下求解且能考量公平性與行車方式的模式，以利於規劃適當地清運路線。 由於路網中存在有單向收集、雙向收集以及不須收集的道路，情形甚為復雜，因此本研究首先針對混合型城市路網（Mixed Network）發展一個前處理方法，藉由最小成本流（Minimum Cost flow method）的觀念找出行駛成本最小的全有向（totally directed）擴張路網（Augmented Network），繼而將沿街收集以線點等價轉換方式為沿點收集，此轉換可簡化問題及利於求解。之後針對此擴張轉換後的路網建立一混合整數模式，模式中並考慮工作負荷以及轉彎合適性。 本研究以新竹市東區為案例，分別以各車總工作時間、總垃圾收集量、及考慮加權前兩項之和等三項，作為公平性評量依據，結果發現本研究所發展的模式依前述三個不同目標式所求得之結果，顯著改善了原先清潔隊的工作時間差異，自29.8分鐘降為1分鐘左右，而垃圾收集差異量則自原先的1796公斤控制為500公斤以內，除此之外模式所求得之解亦改善了原先不當轉變計：迴轉42~83%，左轉68~70%。而原先重復行駛情形由原始綜圖與模式求得之路線圖比較，亦可看出有顯著改善。

The municipal solid waste collection routing is an important issue for waste management and the privatization policy that was recently initiated. Yet, the traditional experience-basedmethod is not capable of responding rapidly various demand and situation changes. An appropriated routing tool is trerefore explored. Furthermore, research in the routing field concentrated mostly on the reduction of cost, and the equity of workload among the collection crew and collection safety and convenience may be thus neglected. In this study, a mathematical model that can be resolved within reasonable computationsal time was proposed. The model considers, in addition to the cost, both the workload equity and vehicle turning efficiency. The complex structure of a real city street network makes it necessary to consider simultaneously directed, un-directed, and the not-served streets. Such a network is difficult to resolve by using a general routing model. For improving the model solvability, the original city street network is transformed to a totally dircted augmented network by a pre-treatment method developed based on the Minimum Cost flow. The augmented network is transformed again by the arc-to-node niethod into an equivalent node-based network. The finally transformed network is then possible to be resolved by using the proposed model within reasonable computational time. A case study in the east region of Hsinchu City was conducted. Total working time, total waste quantity, and the weighted sum of both previous measures are the three workload equity criteria studied. The result shows significant improvement in workload distribution, collection time, and vehicle turning efficiency, when compared with the current collection routing schedule.