UNCORRECTED PROOF Chapter 14 1 Heuristic Solution Techniques for No-Notice 2 Emergency Evacuation Traffic Management 3 Saif Eddin Jabari, Xiaozheng He, and Henry X. Liu 4 Introduction 5 Ground AQ1 transportation systems play a central role during evacuation processes. As 6 responding to unanticipated (no-notice) events (e.g., terrorist attacks, chemical 7 spills, unanticipated structural failures) directly involves human life, the ability 8 to determine optimal traffic management strategies in a timely fashion is crucial. 9 Unlike predictable emergency scenarios, the size and nature of impact of no-notice 10 events cannot be anticipated. This entails adopting measures of a responsive nature 11 and with very little luxury with regards to computation time. 12 From a modeling standpoint, many-to-one dynamic system optimum (DSO) 13 models that embed the cell transmission model (Daganzo 1994, 1995) have become 14 accepted candidates for evacuee routing in an emergency evacuation, where the 15 single destination represents safety and the use of the cell transmission model 16 (CTM) incorporates the entire fundamental diagram, thus capturing a richer level 17 of traffic flow dynamics. As shown in Lo (1999a), embedding the CTM in 18 dynamic traffic assignment formulations results in mathematically complex models; 19 specifically, mixed integer programming techniques are used for this purpose. 20 A simpler formulation was proposed by Ziliaskopoulos (2000), which relaxes the 21 flow restriction constraints in the CTM, thereby modeling the DSO as a linear 22 program (LP), but allowing for traffic holding in the cells, a problematic feature 23 from an implementation standpoint as discussed in Shen et al. (2007). Furthermore, 24 despite the linearity of the relaxed formulation, large numbers of variables and 25 constraints would typically be required to model a moderately sized problem and 26 computation times of classical LP solution techniques are preventative for no-notice 27 S. E. Jabari () · X. He · X. Liu Department of Civil Engineering, University of Minnesota – Twin Cities, 500 Pillsbury Dr. S.E., Minneapolis, MN 55455, USA e-mail: jabar005@umn.edu; hexxx069@umn.edu; henryliu@umn.edu D.M. Levinson et al. (eds.), Network Reliability in Practice, Transportation Research, Economics and Policy, DOI 10.1007/978-1-4614-0947-2 14, © Springer Science+Business Media, LLC 2011