LSU HURRICANE CENTER Addressing Hurricanes and Other Hazards and Their Impacts On the Natural, Built and Human Environments Recent Lessons Learned in Highway-Based Evacuations Brian Wolshon, Ph.D., P.E. Dept. of Civil and Env. Engineering From Ivan to Katrina:

Primary Evacuation Routes In the “Ivan Plan” Normal Flow Contraflow

Problems Identified in Ivan An over-reliance on the westward movement of traffic Confluence congestion created by the confluence of major evacuation routes in Baton Rouge, Hammond, Lafayette, Covington, and Slidell Inefficient loading of contraflow in New Orleans Inability to access up-to-date traffic information and provide timely and accurate traveler information to evacuees LSU HURRICANE CENTER

Map Source: Regional Planning Commission (10/04) Traffic Data Source: LDOTD 48-hour Traffic Volume Counts September 14th and 15 th, 2004 W.B. I-12 73,550 veh. N.B. I-55 60,721 veh. E.B. I-10 30,644 veh. W.B. I-10 79,417 veh. W.B. US-61 33,612 veh. W.B. I ,241 veh. W.B. US190 54,847 veh. N.B. I-49/US-90 64,510 veh. N.B. I-49 57,986 veh. W.B. I-10 64,026 veh.

New Orleans Contraflow Initiation Point Westbound I-10/Loyal Drive Interchange Median Crossover

Photo Source: A. Caterella-Michel Urban Systems, Inc. Hurricane Ivan Evacuation - Interstate 10 (west of New Orleans)

Figure Source: LaDOTD

Proposed Solutions LSU HURRICANE CENTER Maximize the available routes out of the New Orleans area Mitigate (eliminate?) the congestion in Baton Rouge Inefficient loading of contraflow in New Orleans Inability to access up-to-date traffic information and provide timely and accurate traveler information to evacuees

New Orleans Alternatives Ivan w/o contraflow49,464 veh123,660 people----- Ivan w/contraflow 67,224 veh168,060 people35.9% I-10/I-610 Loading Plan 97,572 veh243,930 people97.3% Scenario12h volume at max. flowEvacuees moved Increase over no-c/f

Baton Rouge Alternatives I-12 (bef. interchange)16 mph 2,834 vph56 mph 5,422 vph I-10 (MS River Bridge)28 mph 4,029 vph22 mph 4,399 vph I-110 (aft. interchange)48 mph 2,067 vph55 mph 3,701 vph Location Ivan – Speed Flow Rate w/Contraflow – Speed Flow Rate

Map Source: LaDOTD

Key Concepts - General An evacuation of New Orleans will have consequences throughout the region –Impacts will be felt throughout Louisiana (particularly Baton Rouge) and Mississippi Regardless of what actions are taken, some degree of congestion is inevitable –Evacuations typically result in “too much” demand over “too short” a period Demand may be lowered by: –Encouraging the use of all available routes, not just interstate freeways –Temporally and spatially spreading out the loading of contraflow segments –Dispersing traffic in all “useable” directions (i.e., north in addition to west in Ivan) –Encouraging the “early” closure public offices in New Orleans and Baton Rouge LSU HURRICANE CENTER

Key Concepts - General “Forced” movements are more likely to keep traffic moving –Plans should seek to eliminate or at least reduce decision points and their associated merging/weaving (and made clear to evacuees well in advance) –A policy should be: “Leave early and go where you want. Leave late and go where you are told.” –Suggest everyone evacuate with a full tank of gas and a map in the car as a part of seasonal hurricane preparedness messages. LSU HURRICANE CENTER

Key Concepts - Contraflow Contraflow will not “solve” all evacuation problems –It is only one tool to help address the problem Decisions at origins and destinations (particularly for contraflow) are linked –Routes without efficient loading points and unloading points will not operate effectively –Plans must consider what “goes in” and “what comes out” in tandem –For instance, a New Orleans evacuation will require actions in Baton Rouge –Routes such as the Causeway are not viable reversible candidates because they do not have adequate outflow capacity LSU HURRICANE CENTER

Key Concepts - Contraflow “Split” terminations work better than “Merge” Terminations –Merge configurations can be effective if enough traffic is removed prior to the termination using intermediate exits LSU HURRICANE CENTER

Key Concepts - Policy Define and prioritize the goals of future evacuations and develop plans consistent with these goals –Get people outside of the threat zone? –Minimize travel time to destinations? Maximum flows are likely occur at lower than free flow speed –Maintain a high degree of flexibility (route options) for evacuations Plans must maintain flexibility –Anticipate (and be prepared for) changes as conditions change LSU HURRICANE CENTER

Key Concepts - Policy It was apparent in this effort that we know much less than what we do not know States should consider more comprehensive regional O-D studies that integrate evacuation behavior, travel demand modeling, and operational analyses –This can be used to identify: Areas of likely congestion Underutilized routes Susceptible populations –This information can then be used to develop best policies to address these issues LSU HURRICANE CENTER

LSU Acknowledgements Many of the ideas presented are based on the work of the joint Louisiana DOTD-Louisiana State Police post-Ivan Hurricane Evacuation Task Force, involving experts from: -Louisiana Department of Transportation and Development -Louisiana State Police -Louisiana State University -Urban Systems Inc. -ABMB Engineers, Inc.

Photo Source: Lt. John Denholm Harris Co. (TX) Sheriff's Office Hurricane Rita Evacuation - Interstate 45 (north of Houston)