| In this dissertation, two new performance measures for a transportation network, capacity reliability and capacity flexibility, are researched to handle uncertainty, which exists in both supply (infrastructure such as roadways) and demand (travelers' demand). On the supply side, capacity reliability is the measure that takes into account the uncertainties associated with link capacity degradation due to physical and operational factors. On the demand side, capacity flexibility is used for measuring the ability of the system to handle the uncertainties associated with traffic demands in terms of volume and pattern changes due to technology, economic growth, and some usual/unusual events.; The improved network capacity estimation in terms of models and algorithm is proposed and applied to characterize and quantify these measures. The new features of the improved capacity models allow the researcher to assess the capacity reliability for different concepts under different conditions such as level of uncertainty and level of service. For the assessment of capacity flexibility, the definition of capacity flexibility for a transportation network for passengers is proposed and the approaches to measure capacity flexibility are developed. The new features of improved capacity models also make it possible for the researcher to assess the capacity flexibility in accommodating the variation demand pattern in addition to changes in traffic volume.; This research addresses questions regarding how reliable a transportation network is in accommodating various traffic demands, given the uncertainty in terms of link capacity degradation, and how flexible a transportation system is in accommodating the uncertainty of traffic demand. |
