1 Evacuation Route Planning: Scalable Approaches Shashi Shekhar McKnight Distinguished University Professor Director, AHPCRC University of Minnesota [email protected]March 8th, 2006 Presentation at ITS Minnesota Plans are of little importance, but planning is essential -- Winston Churchill Plans are nothing; planning is everything. --
Why Evacuation Planning?. Hurricane Andrew Florida and Louisiana, 1992. Lack of effective evacuation plans Traffic congestions on all highways Great confusions and chaos. - PowerPoint PPT Presentation
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Evacuation Route Planning: Scalable Approaches
Shashi ShekharMcKnight Distinguished University Professor
Plans are of little importance, but planning is essential -- Winston Churchill Plans are nothing; planning is everything.-- Dwight D. Eisenhower
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Why Evacuation Planning? Lack of effective evacuation plans Traffic congestions on all highways Great confusions and chaos
"We packed up Morgan City residents to evacuate in the a.m. on the day that Andrew hit coastal Louisiana, but in early afternoon the majority came back home. The traffic was so bad that they couldn't get through Lafayette." Mayor Tim Mott, Morgan City, Louisiana ( http://i49south.com/hurricane.htm )
( FEMA.gov)
Hurricane Rita evacuees from Houston clog I-45.
( www.washingtonpost.com)
Hurricane AndrewFlorida and Louisiana, 1992
Hurricane RitaGulf Coast, 2005
( National Weather Services)
( National Weather Services)
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Homeland Defense & Evacuation Planning
Preparation of response to a chem-bio attack
Plan evacuation routes and schedules
Help public officials to make important decisions
Guide affected population to safetyBase Map Weather
Data
Plume Dispersion
Demographics Information
Transportation Networks
( Images from www.fortune.com )
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Problem Statement
Given• Transportation network with capacity constraints• Initial number of people to be evacuated and their initial locations • Evacuation destinations
Output• Routes to be taken and scheduling of people on each route
Objective• Minimize total time needed for evacuation• Minimize computational overhead
Constraints• Capacity constraints: evacuation plan meets capacity of the network
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Limitations of Related Work
Linear Programming Approach
- Optimal solution for evacuation plan
- e.g. EVACNET (U. of Florida), Hoppe and Tardos (Cornell University).
- e.g. EXIT89(National Fire Protection Association)
Limitation: - Do not consider capacity constraints
- Very poor solution quality
Number of Nodes 50 500 5,000 50,000
EVACNET Running Time 0.1 min 2.5 min 108 min > 5 days
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Related Works: Linear Programming Approach
Step 1: Convert evacuation network into time-expanded network with user provided time upper bound T.
G : evacuation network
Step 2: Use time-expanded network GT as a flow network and solve it using LP min. cost flow solver (e.g. NETFLO).
GT : time-expanded network (T=4)
(Source of network figures: H. Hamacher, S. Tjandra, Mathmatical Modeling of Evacuation Problems: A state of the art. Pedestrian and Evacuation Dynamics, pages 227-266, 2002.)
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Proposed Approach• Existing methods can not handle large urban scenarios
• Communities use manually produced evacuation plans
• Key Ideas in Proposed Approach
• Generalize shortest path algorithms
• Honor road capacity constraints
• Capacity Constrained Route Planning (CCRP)
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Performance Evaluation
Experiment 1: Effect of People Distribution (Source node ratio)
Results: Source node ratio ranges from 30% to 100% with fixed occupancy ratio at 30%
Figure 1 Quality of solution Figure 2 Running time
• SRCCP produces solution closer to optimal when source node ratio goes higher
• MRCCP produces close-to-optimal solution with half of running time of optimal algorithm
• Distribution of people does not affect running time of proposed algorithms when total number of people is fixed
Emergency Planning Zone (EPZ) is a 10-mile radius around the plant divided into sub areas.
Data source: Minnesota DPS & DHS Web site: http://www.dps.state.mn.us
http://www.dhs.state.mn.us
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Destination
Monticello Power Plant
Handcrafted Existing Evacuation Routes
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A Real Scenario – Overlay of New Plan Routes
Source cities
Destination
Monticello Power Plant
Routes used only by old plan
Routes used only by result plan of capacity constrained routing
Routes used by both plans
Congestion is likely in old plan near evacuation destination due to capacity constraints. Our plan has richer routes near destination to reduce congestion and total evacuation time.
Twin Cities
Total evacuation time:
- Existing Routes: 268 min.
- New Routes: 162 min.
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Project 2: Metro Evacution Planning (2005)
Agency Roles
Identify Stakeholders
Establish Steering
Committee
Perform Inventory of
Similar Efforts and Look at
Federal Requirements Finalize
Project Objectives
Regional Coordination
and Information
Sharing
Metro Evacuation Plan
Stakeholder Interviews and
Workshops
Evacuation Route
Modeling
Evacuation Routes and Traffic Mgt.
Strategies
Issues and Needs
Final Plan
Preparedness Process
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Road Networks
1. TP+ (Tranplan) road network for Twin Cities Metro Area
Source: Met Council TP+ dataset
Summary: - Contain freeway and arterial roads with road capacity, travel time,
road type, area type, number of lanes, etc.- Contain virtual nodes as population centroids for each TAZ.
Limitation: No local roads (for pedestrian routes)
• Source: MN Dept. of Employment and Economic Development - Contain work origin-destination matrix for each Census block.- Need to aggregate data to TAZ level to obtain: Employment Flow-Out: # of people leave each TAZ for work. Employment Flow-In: # of people enter each TAZ for work.
• Limitation: Coarse geo-coding => Omits 10% of workers
• Does not include all travelers (e.g. students, shoppers, visitors).
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Scenarios
• Sources:• Prioritized list of vulnerable facilities and locations in Twin Cities
• Federal list of scenarios – Subset requiring evacuation
• Input from advisory board and stakeholder workshop
• Selected Scenarios
1. Downtown 1
2. Downtown 2
3. University
4. Mall
5. Suburban Facility
• Scenario Specification for Evacuation Route Planning• Explicit
• Source = < Location Center, Footprint Circles >
• Destination = choice ( fixed locations OR outside a destination circle)
• Implicit (Estimates from databases) with user overrides
• Transportation Network – connectivity, capacities, travel times