Modeling the impact of traffic management strategies on households' stated evacuation decisions

Evacuation traffic management has been implemented in large-scale disaster evacuations (such as hurricanes) to facilitate traffic flow and reduce travel delay. The outcomes of these strategies were quantified via traffic simulation but were assumed to have no/limited impacts on households' evacuation-related decisions. This study analyzed and modeled the impact of these strategies on five evacuation related household choices (evacuate/stay, departure time, route, vehicle, and destination) separately based on 415 responses collected from a stated preference survey. The survey was conducted in 2017 in coastal areas near Hampton Roads. Traffic management is likely to motivate some (32%) households to evacuate instead of sheltering in place. In addition, not all households take the interstates with traffic management even though route choice is the most likely to be affected by traffic management. Households need more information for their departure time and destination choices in response to traffic management since they are more likely to feel uncertain of the impact of the strategies on these decisions. Such uncertainty in departure time and destination choice is especially true for those who evacuate late and for those who choose accommodations other than the home of friends/relatives. Emergency management agencies should also be aware that some households may intentionally depart before traffic management starts. Among the five choices, vehicle use is the choice that is least likely to be affected. All the above-mentioned findings potentially affect parameter specifications in evacuation traffic simulation studies. This study then used multinomial logit models to estimate the impacts of traffic management on each of the five evacuation related choices. The model estimation results can help improve evacuation demand predictions and guide evacuation information dissemination.

在大规模灾害疏散（如飓风）中，已实施疏散交通管理以促进交通流畅并减少出行延误。这些策略的效果通过交通模拟进行了量化，但被假定对家庭与疏散相关的决策没有/只有有限的影响。本研究基于从一项陈述偏好调查中收集的415份回复，分别分析并模拟了这些策略对五个与疏散相关的家庭选择（疏散/留下、出发时间、路线、交通工具和目的地）的影响。该调查于2017年在汉普顿锚地附近的沿海地区进行。交通管理可能会促使一些（32%）家庭进行疏散而非就地避难。此外，尽管路线选择最有可能受到交通管理的影响，但并非所有家庭都会选择有交通管理的州际公路。家庭在根据交通管理做出出发时间和目的地选择时需要更多信息，因为他们更有可能对这些策略对这些决策的影响感到不确定。对于那些晚疏散的人和那些选择朋友/亲戚家以外住宿的人来说，出发时间和目的地选择的这种不确定性尤其明显。应急管理机构也应该意识到，一些家庭可能会故意在交通管理开始之前出发。在这五个选择中，交通工具的使用是最不可能受到影响的选择。上述所有发现都可能影响疏散交通模拟研究中的参数设定。本研究随后使用多项逻辑模型来估计交通管理对五个与疏散相关的选择中每一个的影响。模型估计结果有助于改进疏散需求预测并指导疏散信息传播。