本文首先證明出n階段(n=1，2，3，...)的階梯式擁擠收費模式中諸項規律性特徵之存在，根據這些規律性的特徵值，則可方便吾人探討在排隊擁擠的瓶頸路段實施階梯式擁擠收費時，供方 (政府) 與需方 (通勤者) 因收費階段數之遞增所分別形成的遞增典遞減成本函數。最後在雙方之總成本最小的原則下求得階梯式擁擠收費體制下之最佳收費階段數，使階梯式擁擠收費能得到最佳運作。以上之推導結果乃是階梯式擁擠收費之理論模式中尚未被討論到的部分，故本文除了對既有理論模式之盲點有所突破外，更可提供政策執行單位在實務操作上之遵循依據。

This paper proves that there exist some regular characters to the model of the optimal n-step tolls (n = 1, 2, 3, ..-). According to these regular results, we can then derive the optimal number of pricing steps, which minimizes the total costs for the demand and supply sides, for the step toll scheme implemented at a queuing road bottleneck. These outcomes, which have not been discussed previously, not only improve the theoretical model of the step toll scheme, but also provide the authorities a rule to operate the optimal step toll in practice.