For communities threatened by hurricanes, evacuation time estimate (ETE) computation requires developing sophisticated evacuation flow models through analysis. In the last 25 years, significant progress has been made in this area. Accurate assumptions about risk area population behavior is required for ETEs, however, but evacuation models developed by transportation engineers have been poorly integrated with population behavior research by social scientists. The authors describe available ETE model-relevant empirical data, principal behavioral variables affecting hurricane ETEs, and recommended future analytic research and methods to address the disparity.

Critical Behavioral Assumptions in Evacuation Time Estimate Analysis for Private Vehicles: Examples from Hurricane Research and Planning

Dynamic traffic simulation models are frequently used to support decisions when planning an evacuation. This contribution reviews the different (mathematical) model formulations underlying these traffic simulation models used in evacuation studies and the behavioural assumptions that are made. The appropriateness of these behavioural assumptions is elaborated on in light of the current consensus on evacuation travel behaviour, based on the view from the social sciences as well as empirical studies on evacuation behaviour. The focus lies on how travellers’ decisions are predicted through simulation regarding the choice to evacuate, departure time choice, destination choice, and route choice. For the evacuation participation and departure time choice we argue in favour of the simultaneous approach to dynamic evacuation demand prediction using the repeated binary logit model. For the destination choice we show how further research is needed to generalize the current preliminary findings on the location-type specific destination choice models. For the evacuation route choice we argue in favour of hybrid route choice models that enable both following instructed routes and en-route switches. Within each of these discussions, we point at current limitations and make corresponding suggestions on promising future research directions.

/pdf/a-review-on-travel-behaviour-modelling-in-dynamic-traffic-24kiauvwhn.pdf

A review on travel behaviour modelling in dynamic traffic simulation models for evacuations

Multi-objective evacuation routing in transportation networks

Residential development in fire-prone wildlands is occurring at an unprecedented rate. Community-based evacuation planning in many areas is an emerging need. In this paper we present a method for using microscopic traffic simulation to develop and test neighborhood evacuation plans in the urban–wildland interface. The method allows an analyst to map the subneighborhood variation in household evacuation travel times under various scenarios. A custom scenario generator manages household trip generation, departure timing, and destination choice. Traffic simulation, route choice, and dynamic visualization are handled by a commercial system. We present a case study for a controversial fire-prone canyon community east of Salt Lake City, Utah. GIS was used to map the spatial effects of a proposed second access road on household evacuation times. Our results indicate that the second road will reduce some household travel times much more than others, but all evacuation travel times will become more consistent.

Microsimulation of neighborhood evacuations in the urban - wildland interface

Little attention has been given to estimating dynamic travel demand in transportation planning in the past. However, when factors that influence travel are changing significantly over time, such as with an approaching hurricane, dynamic demand and the resulting variation in traffic flow on the network become important. The decision to evacuate in the face of an oncoming hurricane is considered as a series of binary choices over time. A sequential binary logit model is developed to model the probability that the members of a household will evacuate at each time period before hurricane landfall as a function of the household's socioeconomic characteristics, the characteristics of the hurricane, and policy decisions made by authorities as the storm approaches. Data collected in southwest Louisiana after Hurricane Andrew were used to estimate a model that produced dynamic travel demand estimates of hurricane evacuation. On the basis of the results, a sequential logit model appears to be capable of modeling dy...

http://www.ltrc.lsu.edu/pdf/TRB2004-000960.pdf

Sequential logit dynamic travel demand model for hurricane evacuation

A methodology based on probabilistic mobilization time curves and pertinent evacuation network details is described for estimating the times required for the partial or total evacuation of an emergency planning zone (EPZ). Such an EPZ evacuation study is required by the U.S. Nuclear Regualatory Commission (NRC) for existing and proposed nuclear power operating plants. Inputs and outputs for the resulting computer model developed from the methodology are discussed for a nuclear power plant licensing application by Public Service Company of Oklahoma. With typical input conditions for the example under consideration, the computer model predicted an average total evacuation time of approximately two and a half hours, excluding notification and confirmation times.

Stephen W. Tweedie

Papers

A methodology for estimating emergency evacuation times

Viewing the Bible Belt