Extended cell-transmission-based evacuation planning in urban areas

Abstract

ABSTRACT.A well-known traffic simulation model bases on the idea to represent street sections by socalled cells where vehicles are streaming from one cell to another in order to give a realistic image of traffic flows. Its basic ideas were picked up recently to formulate an optimization model for evacuation planning purposes. We will address three major weaknesses of the recent model, namely the usage of a fixed single cell size, missing consideration of lanes as well as missing limitations for traffic flows and show how to overcome them. Stimulated by this, we formulate the extended Cell-Transmission-Based Evacuation Planning Model and a new optimization model to facilitate this model in terms of choosing the optimum cell size. Additionally, we will present an iterative simulation-based optimization approach in order to evaluate and to enhance results in a more realistic environment. This approach takes advantage of a standalone vehicle reallocation optimization model, additional traffic flow limitations as well as a state-of-the-art microscopic traffic simulation. We will demonstrate the effectiveness of this approach in a real-world example.

Cell-transmission-based evacuation planning with rescue teams

“…The conversion of a given network into a cell-based network is a challenging task, especially when multiple cell sizes and driving speeds are used. For this task, Kimms and Maassen (2011b) developed an optimization model, which determines the "optimal" cell size in a way that the number of cells under consideration of a given level of accuracy in network representation will be minimized. Since the cell-based network does not need to be modified for evacuation planning with rescue teams, this approach can be adopted without adjustments for this paper.…”

“…Hence, a cell of size n can be passed in at least n periods and I n is the index set of cells of cell size n. The parameter n i indicates the size of cell i. More detailed explanations can be found in Kimms and Maassen (2011b). Furthermore, the index set of periods is T = {1, .…”

“…According to Kimms and Maassen (2011b), logical constraints are needed to describe relations between structural decision variables and to guarantee real-worldapplicability:…”

“…Therefore, Kimms and Maassen (2011b) developed so-called "traffic flow limitation" constraints, see Eqs. 36-39.…”

“…Furthermore, the size of test networks massively differs, e.g. small networks in Chiu et al (2007), Shen et al (2007) and Xie et al (2010), medium networks in Kimms and Maassen (2011a) and Tuydes and Ziliaskopoulos (2004) as well as large networks in Kalafatas and Peeta (2009), Kimms and Maassen (2011b), Tuydes and Ziliaskopoulos (2006) and Yue et al (2008). Kalafatas and Peeta (2009) and Xie et al (2010) decide to increase level of detail by using one cell per driving direction instead of one cell per street segment like the other authors.…”