## 2 Literature Review  
Previous studies evaluating the impact of highway link disruption have focused primarily on the economic impacts, rerouting strategies, and retrofit priorities. [PERSON] et al. [1] estimated the transport-related business interruption impacts of the 1994 Northridge earthquake using a spatial allocation model. The National Research Council [2] suggested a decision analysis process for modeling the economic impact on the freight system by transportation facilities and link disruptions. The process consists of rerouting, supply-chain response, and industrial impact evaluation. [PERSON] et al. [3] estimated the economic impacts of disruption by combining the transportation network and economic input-output model. [PERSON] et al. [4] and [PERSON] [5] studied rerouting strategies and the robustness of highway links following natural disasters. Those economic impact analyses could have been used to estimate the overall loss of the economic activities caused by the disruption and identify the most significant links on the network in an economic sense. However, those methodologies cannot be applied to investigate detailed day-to-day movement of people in the region before and after the disruption. As [PERSON] et al. [6] noted, recent studies have begun to pay close attention to the sequential application of traffic equilibrium models to measure the traffic change by a disruption. For example, [PERSON] et al. [7] developed a spatial equilibrium model to estimate the freight and passenger flow from link disruption following an earthquake. [PERSON] and [PERSON] [8] validated a day-to-day traffic evolution model with empirical observations on the collapse of the I-35W Mississippi River Bridge. The focus of those studies was limited to the highway vehicle users without considering the converted demand to the public transit system. There are several studies regarding the behavior changes of commuters during planned or unplanned highway closures. Most of those studies are based on telephone, mail, Internet, and in-person surveys. These studies include the following: maintenance-related closures of the Fix I-5 project in Sacramento, CA [9], 1-405 in Seattle, WA [10], Southeast Expressway in Boston, MA [11], I-376 in Pittsburgh, PA [12], and the Centre Street Bridge in Calgary, Canada [13], in addition to disasters, such as the I-35W Bridge Collapse in Minneapolis, MN [14], and the Northridge earthquake [15,16]. [PERSON] and [PERSON] [17] measured overall transportation system performance after area-wide highway system damage following the 1995 Kobe, Japan earthquake. They proposed system-wise performance measures, including total length of the network that was open, total distance-based accessibility, and areal distance-based accessibility. [PERSON] and [PERSON] [18] tested the influence of travel time information to drivers in rerouting traffic after the closure of the Hanshin Expressway in Japan. Literature on transportation system performance in disasters is summarized by [PERSON] and [PERSON] [19]. A recent study by [PERSON] et al. [20] on the I-35W Bridge collapse in Minneapolis, MN analyzed traffic detector and bus ridership data with the survey results, including aggregated weekly and daily traffic counts, total vehicle kilometers of travel, vehicle hours of travel, and monthly transit ridership. They reported that the total travel demand on the highway was not reduced significantly after the network collapse because of redundant capacity provided by alternate routes. The peak period, however, was extended and the total travel time was increased. The increase of bus ridership was not evident, but it is noted that the follow-up studies are necessary to investigate impacts of bridge collapse on transit ridership in detail.