由於私人運具的成長對於國道運輸造成衝擊，因此主管機關應以系統化的角度進行思考如何確實反映尖峰時間使用國道所應付出的價格。國道費率定價的制定必須能夠達到「替代效果」，此替代效果包含時間替代、道路替代以及運輸工具的替代。鑒此，本研究建構國道收費定價最佳化設計雙層規劃模型。上層問題為系統最佳化，追求路網總成本最小為目標；下層問題則利用含額外限制之依時性用路人最佳化運具選擇／路徑選擇／出發時間選擇模型的特性，分析最佳化費率下依時性用路人旅運行為。使得用路人因有效的道路定價產生道路替代、運具替代以及出發時間替代的效果，進而規劃出切實有效的最佳化費率，作為未來政策推行的依據。

Rapid growth in private vehicle ownership has led to congestion and inadequate service on freeways. The authorities should promote the road pricing strategy in a systematic view that accurately reflects the cost of using the freeway during peak hours is required. The pricing strategy must achieve the “alternative effect” which includes departure time replacement, path substitute and modes alternative. This study formulate the time-dependent bi-level model for road pricing on freeways which integrates time dimension, route choice and mode choice factors. The upper level objective of the model is to minimize the total network costs. The objective of the lower level is to apply the time-dependent user-optimal mode choice/departure time/route choice model with side-constraints to analyze the behavior of the travelers under optimal toll rates. The users will be affecting by efficiency road pricing and changing the behavior. The results can be used as reference in establishing public policies that facilitate effective toll rates.