Highway Evacuations in Selected Metropolitan Areas: Assessment of Impediments
INRIX® National Traffic Scorecard 2009
Portland and Oregon State officials noted that to address mass evacuations, planners must first answer the question "What would cause us to evacuate the city?" Portland urban area residents are vulnerable to no-notice events, such as earthquakes, wildland/urban interface fires, landslides, and volcanoes; however, none of which would trigger a full-scale evacuation. These no-notice events complicate transportation responses due to the range of locations that might need to be evacuated. Moreover, in most cases, authorities would encourage residents to shelter-in-place.
The city of Portland conducted a 2008 Gap Analysis that identified regional planning as a needed component of the City of Portland Evacuation Annex update. Information from the 2008 workshop series examined roles and responsibilities, alternate transportation routes, route carrying capacity, and a decision matrix to determine mass-care site criteria. These three reports, or "Technical Memoranda," along with the emergency exercise and incident reports, will support regional evacuation planning efforts in 2010.
State and city authorities met recently to discuss deficiencies of the transportation system. The group addressed transportation as related to mass evacuations. The group agreed that:
- there would be no or little notice for most events which would cause populations to evacuate;
- no current hazard faced by the region would trigger a mass evacuation;
- planning must focus on localized evacuations if one was deemed necessary;
- notification of the public will be problematic;
- planning must be adaptable to population diversities and behaviors;
- regional planning for evacuation is necessary because of shared assets, resources and liabilities; and
- the current ground transportation system is at its capacity.
Transportation, police, emergency management and fire agencies also concluded that contraflow techniques, although highly unlikely and situation dependent, could be planned for and accomplished for localized and small scale events.
Top Highway Impediments
Top Highway Impediments
- Bridge Vulnerability
- Capacity & Infrastructure Limitations
- Communications & Coordination with Neighboring Jurisdictions & the Public
- Communications & ITS Technology for Incident Operations
- Improved Traffic Management & Safety
- More Robust Planning for Evacuation Operations
- Identification & Use of Resources
Respondents identified the most significant impediments along NHS routes that may impact effective large-scale, mass evacuations from the Portland metropolitan area. These include:
- Bridge Vulnerability - Portland evacuees must navigate over many bridges that may be vulnerable to damage or closure during an event. The city of Portland is divided by the Willamette River and bordered to the north by the Columbia River which divides the States of Oregon and Washington. Four highway bridges traverse these rivers. Only 2 of the four bridges have been earthquake-retrofitted, and all of the bridges sit in liquefiable soil adding to the instability of major transportation corridors. The bridges pose a highly vulnerable link in the transportation infrastructure, so the region is affected if the bridges are impacted.
The city owns 157 overpasses and bridges, none of which cross the Columbia or Willamette rivers. In an earthquake, these overpasses could fall onto the major thruways of the region and interfere with emergency response vehicle transport. Emergency Transportation Routes8 have been identified and listed in priority order for damage assessment and coordination.
- Capacity and Infrastructure Limitations - In Portland, the NHS roadway infrastructure operates at capacity during peak periods. This is most noticeable at the slightest stall of a car in rush hour, which delays traffic and impedes response vehicles. This situation would be greatly exacerbated if officials conducted an evacuation operation over these roads. Several choke points in the urban area cause problematic congestion and would greatly restrict evacuation operations in these areas. Through a 2007 study, the Portland Operations Steering Committee identified the primary reasons for congestion and made recommendations. Information gathered from this report will be included in mitigation and education plans in preparation for evacuation.
- Communications and Coordination with Neighboring Jurisdictions and the Public - Regional coordination needs to address coordinated use of technology, collaborative planning, communication between agencies and between agencies and the public, management of multiagency responses and cooperative agreements that document the decisions between agencies, jurisdictions and disciplines. Authorities continue to plan public communication strategies. Regional public information concept of operations and public messaging templates are currently being validated within the region. Warning Annexes, DMS, cameras and Web site capabilities are being examined with the intent of greater cooperation in traffic management during extreme situations. Authorities also noted that the region must develop agreements for response and mitigation of roads traversing and impacting multiple jurisdictions.
A focal point of communication was consistent messaging and the strategy to develop and implement agreed upon messages for the public. Different from the technology tools, communication strategies relates to what is in the message, who is involved in the message transmission and what the content of the different messaging strategies are (e.g., policy, decisions, warning or education).
- Communications and ITS Technology for Incident Operations - Authorities noted that the region must make better use of communication and other ITS technology. Transportation agencies in the Portland urban area have many technological tools at their disposal for use in communicating with the public and with each other. The problem and the deficiency in these tools are their interconnectivity, interoperability and integration into emergency response. An ITS for the region includes the typical metropolitan systems: CCTV video recording, DMS, TOCs at both Oregon DOT (ODOT) and the city of Portland, traffic signal operations and highway system cameras. Regional partners use ITS primarily for day-to-day traffic and incident management. An adequate number of DMS on arterial streets and enough to be placed at a distance from an incident were identified as needs.
Some TIM corridors exist where the counties, Portland and ODOT have placed route guidance and improved signal operations on parallel routes to the highway system. Deficiencies in networking capability and the interoperability of communications between agencies were identified as top impediments to the operations of evacuations. With so many tools to use, the difficulty becomes the reliability and consistency of the message. Internet communications technologies such as Twitter, Facebook, TripCheck, transit Automated Rider Boards, public alerts, Web EOC and Ops Center all are rapidly developing and must be included, tracked and documented through agreements, plans and policies. Public Radio broadcasts and Reverse 911 messages need to be a part of the communications technology plan. A regional Gap Analysis for Public Works regarding interoperability of radio and telecommunications is in the first stage of development as part of a DHS UASI Initiative grant project.
- Improved Traffic Management and Safety - Authorities concluded that the region should focus upon improving safety and traffic flow on multiple road interchanges within the highway system.
- More Robust Planning for Evacuation Operations - Respondents commented that the Portland urban area would like to do more with planning for evacuations. They noted that they must strategically plan to manage multiple modes of transportation and describe it in an evacuation annex. They would like to look at different areas over a 24-hour period and determine the different evacuation needs based on time of day. The urban area population centers, geography and transportation system (including mass transit, bridges/overpasses, road capacity) impact decisions of evacuation planning. Planners are reviewing assets and risks that could impede or improve public service recovery, evacuation or isolation. Regionally, counties are conducting continuity of operations planning to determine service capabilities that could aid the public when disaster strikes and evacuation is or is not implemented. Reception planning has begun through the identification of emergency needs for congregation sites and the criteria for each site's operation. Such sites reviewed are sheltering, transportation connection, points of distribution, medical care points and feeding facilities. The research conducted in 2008 will enhance discussions about adjacent counties within the urban areas reception centers in the next phases of evacuation planning.
- Identification and Use of Resources - Respondents noted that they need to look at their transportation assets, regional response route map, and regional roles and responsibilities prior to an emergency to identify what might be used, the parameters of use, and how the resource might be adjusted for evacuation operations. While Portland urban area planners have discussed the use of buses for mass evacuation, more understanding of their plans and capabilities are needed. C-Tran has a Bus Mobilization Plan that is coordinated with Clark Regional Emergency Services Agency. However, Tri-Met has no plan and there is no regional emergency management agency with a governance structure to manage such an agreement. Authorities must know the limitations of public and private transportation resources during disaster, and agreements need to be drawn between the agencies. Many multicounty agreements have been created that allow sharing of resources and accountability for those resources in disaster. But there is a regional shortage of current private resources that can be used in any response including evacuation. Part of future planning will be to identify the shortage gaps and ways to fill them.