時間價值理論與實證之研究

Abstract

摘要 道路交通量的急速增加使得中央及地方政府增加道路系統的投資，但是我們很難去計算這些因為投資所產生的價值及效用。為了解決這個問題，於是發展出成本-效益分析法。成本-效益分析法能計算這些投資計劃的經濟效益，提供決策者有系統的資訊。在運輸的成本-效益分析上，時間節省價值是項重要的因素。如果能將時間節省價值轉換成以金錢為衡量的單位，將可以更從容地進行比較與分析。 文獻回顧主要回顧各種衡量時間價值之理論及模型，並討論影響時間價值的因素。而本實證研究採用條件評估法之封閉式條件法及Hanemann(1984)提出封閉式條件法的個體經濟理論基礎，以衡量受訪者的支付意願。根據以上方法，本研究修正Hanemann效用函數，並整理及提出兩種由不同角度計算時間價值的方法(個體法及總體法)，總共五種模型，以進行各項分析。 我們得到以下實證研究結果。假說一假設相同旅行時間長度的旅次，節省時間數量越大，單位時間價值越大，此假說無法得到支持。假說二假設相同節省時間數量的旅次，旅行時間長度越大，單位時間價值越大，此假說得到支持。 社會經濟特性和時間價值有以下的關係，所得、擁有汽車數和時間價值有正向關係，年齡、擁有機車數和時間價值有負向關係，女性的時間價值大於男性。 如果將所得分成高中低三群，分群討論不同所得群的時間價值，大部份的旅次時間價值隨所得增加而增加，成正向關係。而討論不同所得群中，社會經濟特性對時間價值的影響，則低所得群中，年齡大多和時間價值為正向關係，但中高所得群為負向關係。低所得群中，擁有汽車數和時間價值為負向關係，但中高所得群和時間價值為正向關係。 我們最後分析旅次目的對時間價值的影響。新竹到台北節省15分鐘的旅次，以洽公的時間價值最大，通勤次之，以訪友及返家最小。節省時間為30分鐘時，仍以通勤及洽公之時間價值最大，返家最小。新竹到高雄的旅次以洽公的時間價值最大，休閒次之。

ABSTRACT The rapid increase in road traffic has led to increased investment in the road system by central and local governments. But it is hard to estimate the value and utility of the investment. For solving this problem, the technique of cost-benefit analysis was developed. Cost-benefit analysis can estimate benefit and provide decision-maker systematic information. The value of time savings is an important element in transportation cost-benefit analysis. If we can convert the value of time savings into monetized units, it will be easier to compare and analyze. The reference is about the theories and models of measuring the value of time, and we discussed the variables that affect the value of time. We used the closed-ended contingent method of contingent valuation method and the microeconomics theory basis proposed by Hanemann (1984) to measure the willingness to pay of the interviewers. We modified the Hanemann utility function on the basis of above method and we arranged and proposed two methods for measuring the value of time from various angles (aggregate method and individual method), so totally five models have been tested. As to the empirical study, we reached the following conclusions. Hypothesis 1 assumes that for the same trip length, the unit value of time increases when the amount of time saved increases. This is rejected. Hypothesis 2 assumes that for the same amount of time saved, the unit value of time increases when the trip length increases. This is accepted. In our study, social-economic characteristics and the value of time have the following relationship. Income, car-possession and the value of time have positive correlation. Age, motorcycle -possession and the value of time have negative correlation. Women have larger value of time than men. If we divide income into high, medium and low income groups. Most part of the value of time increases when the income increases. Age and the value of time have positive correlation in low income group, but negative correlation in medium and high income groups. Car-possession and the value of time have negative correlation in low income group, but positive correlation in medium and high income groups. We analyze the effects the purposes of trip have on the value of time. The business trip of Hsinchu -Taipei saving 15 minutes has the largest value of time. Commuting trip has the second one. Visiting and home coming trip have the smallest ones. During saving 30 minutes trip, commuting and business trip have the largest value of time. Home coming trip has the smallest one. The business trip of Hsinchu -Kaohsiung has the largest value of time. Recreation trip has the second one.