截至目前為止，高速公路上利用動態的路段流量資訊推估動態旅次起迄的模式， 以 Chang and Wu (1994) 所建立的模式在實際操作上最為可行。 以往的相關研究由於忽略 了旅行時間所造成時間延滯的影響，因此與現實狀況顯然不符。而 Chang and Wu 的模式和 以往相關研究最重要之不同點在於考慮時間延滯的因素， 並使用了主線道流量資訊。 然而 Chang and Wu 的模式，在加入主線道流量資訊後， 由於未考慮上游路段與下游匝道之時差 ，因此造成模式之狀態變數定義前後不一。另外，此模式推估旅行時間的方法也並不恰當。 所以本研究針對這些缺失進行修正， 提出正確之高速公路動態 O-D 推估模式，並利用密度 -- 速度關係來估算各時段之路段旅行時間，以改良原模式之估算法； 同時提出修正後模式 之求解方式，最後以一個數值例證明修正後模式之可求解性。

　　　　　Up to now, the model which estimates dynamic O-D from dynamic traffic counts on the highway is well developed by Chang and Wu (1994). The major difference between this model and others is its adoption of the time-delay factor and main line traffic counts. Other researchs pay less attention to the factor of travel time, and that does not match with the real situation. However, in Chang and Wu's model using the main line traffic counts without considering the time lag between upstream and downstream makes the definition of state variable ambiguous. After all, the travel time considered in the model can only be used before traffic jams. Our research, therefore, provides a density-speed relation to estimate the travel time of each interval and gives a correct dynamic highway O-D estimates and also improves the problem solving procedure. A numerical example is given to show that this improved model leads to feasible solutions.