靜態旅行時間路段成本函數BPR之校估及應用

Calibration and Application of BPR Function

靜態旅行時間路段成本函數係探討交通需求量及旅行時間的關係，可提供作為總體程序性運輸規劃中交通量指派的依據。本研究以BPR函數為基礎，以省道為研究範圍，校估其參數，以供日後運輸規劃之用。BPR函數的變數包含需求量、容量、自由車流旅行時間等。其中，容量及自由車流旅行時間可以考量部分的旅行時間影響因素。但由於道路兩旁干擾程度未能納入BPR函數的變數中，而地形及車道數等因素又未能於前述BPR變數中完整考量。故本研究根據地形、道路兩旁干擾程度、車道數將路型分為13種類型，以期由BPR函數的參數α及β，反應未能由容量及自由車流旅行時間中完整考量的因素。最後，將各路型之靜態旅行時間推估模式之相關參數值儲存到旅行時間資訊顯示系統之電子地圖資料庫各路段屬性中，以供未來運輸規劃應用參考。

Static link cost function describes the relation between traffic demand (volume) and travel time, and it could be the basis of traffic assignment. The calibration of BPR function is presented in this paper. Variables of BPR function include: traffic demand, capacity, and free flow travel time. Capacity and free flow travel time account for some of the factors influencing travel time. However, some other factors influencing travel time, such as terrain, roadside disturbance, and number of lanes, are not fully considered in BPR function. In this study, roads are classified according to terrain, roadside disturbance, and number of lanes so that the parameters of BPR function can reflect these factors influencing travel time. Finally, the calibration results are saved in an electronic map database, and it could be the basis of conducting relevant transportation planning processes.