# Modeling Evacuees' Intended Responses to a Phased Hurricane Evacuation Order
## 2 Literature Review and Hypotheses  
### Current Practices and Studies of Phased Evacuation  
Phased evacuation is a hurricane evacuation demand-management strategy that is intended to spread peak travel demand over time. The approach typically identifies people who are exposed to greater risk (such as lower-lying areas) and orders these groups to leave the endangered area at an earlier time. The following examples illustrate this approach. Louisiana implements phased evacuation by identifying regions and specifying when they should evacuate: areas south of the Intracoastal Waterway (50 h before the onset of tropical storm winds), areas south of I-10 (40 h before the onset of tropical storm winds), and areas on the east bank of the Mississippi River in the New Orleans metropolitan area (30 h before the onset of tropical storm winds) [4]. How these regions are determined varies. In the example above, natural bodies of water (the Intracoastal Waterway and the Mississippi River) and major highways (I-10) are used, while Texas uses zip codes [9] and Florida uses mile marks [8]. In addition to these descriptions, zones are also often mapped and color-coded for visual presentation, and individuals can check where they are located by entering addresses on interactive webpages or in apps [15]. Studies that predict the benefits of this strategy using optimization or simulation approaches generally assume that evacuees will follow the guidance as ordered and without shifting the departure time, destination, or route [16; 17; 18; 19; 20; 21; 22; 23; 24]. Even with the assumption of full compliance (100%), [PERSON] et al. [25] found that phased evacuation does not significantly improve evacuation performance (in terms of the percentage of completed evacuations and average travel speed) when the level of demand or the congestion in the road network is low. Alternatively, several simulation studies (e.g., [PERSON] et al. [26]) used a fixed partial compliance rate to evaluate whether phased evacuation is an effective demand-management strategy given different assumptions. [PERSON] et al. [26] found that the phased evacuation strategy further improves the traffic situation when it is implemented with the contra-flow strategy, especially for zones of higher risk. [PERSON] et al. [27], who tested multiple assumed compliance rates in their study of optimizing evacuation instructions, even found that lower levels of compliance sometimes lead to higher evacuation efficiency. This body of knowledge, with its mixed results, highlights the importance of additional study to understand compliance rates and their effects on evacuation. Some studies modeled hurricane-evacuation order-compliance behavior without considering phasing. [PERSON] et al. [28] studied evacuation order compliance behavior with a random parameter binary logit model based on data collected from Hurricane Ivan (2004). The statistical significance of the random coefficients for order issuance reveals household heterogeneity in responding to evacuation orders (i.e., order compliance and the presence of shadow evacuation). [PERSON] et al. [29] further distinguished those who received an evacuation order from those who did not with data from Hurricane Matthew (2016). Two separate random parameter logit models were estimated to understand order-compliance behavior and shadow evacuation, respectively. These researchers found that consistent/sufficient warning information and large/diverse social networks both encourage evacuation-order compliance, which reminds public agencies to be consistent in their warning dissemination and pay attention to isolated households. There is a wide range of factors that could influence warning-response behavior. [PERSON] and [PERSON]'s protective action decision model (PADM) is one of the theoretical frameworks that organize factors and was designed for disaster scenarios, specifically [3; 10; 30].