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U.S. Department of Transportation U.S. Department of Transportation Icon United States Department of Transportation United States Department of Transportation

Public Roads - March/April 2004

Coordinating Incident Response

by K. Craig Allred

Guidelines demonstrate how agencies can apply unified command to managing highway emergencies.

Highway incidents vary in type and scalefrom life-threatening traffic-stoppers such as a multivehicle pileup or hazardous material (hazmat) spill on an Interstate to a minor no-injury, one-car crash into a stop sign on a residential street. Because more than half of the situations involving traffic congestion are generated by incident-related delays, highway agencies have a major stake in the efficient management of roadway incident scenes to restore normal traffic flow as quickly as possible.


An incident management system can help emergency responders, police, firefighters, department of transportation personnel, and towing operators coordinate their responses and clear this overturned truck quickly and effectively.

Highway agencies typically have no direct control over how quickly a roadway is cleared after an incident because emergency scenes are controlled by the first-response agencies that have statutory jurisdiction (fire, emergency medical services, and law enforcement). Highway agencies usually are considered "second responders," with a mission to clear the roadway and restore traffic flow after the first responders have addressed the primary mission of protecting public safety and health. In practice, first and second responders usually cooperate to recover normal traffic flow as quickly as possible. But what happens when a crash blocks the roadway longer than necessary, and highway agencies have no influence on decisions about how to manage the incident?

In the 1970s, fire services developed the concept of "unified command" as a way to take into account the missions of all responding agencies when making decisions at the scene of an incident. The ultimate goal was to serve the public interest most effectively. Incident management systems (IMS) were developed to provide the organizational framework for applying the concept of unified command.

The Model Procedures Guide for Highway Incidents, a document developed by the National Fire Service Incident Management System Consortium, shows how an IMS used for many years by the fire service and emergency management agencies can be applied to various types of highway incidents.

Funded by the U.S. Department of Transportation's (USDOT) Intelligent Transportation Systems (ITS) Public Safety Program, the guide adapts the consortium's IMS to highway incident operations. The document provides examples of command structures for a wide variety of highway incident scenariosfrom terrorist events to winter storms, parades, hazmat spills, and typical motor vehicle crashes.

Safety and Traffic Flow: Important Objectives

The Model Procedures Guide for Highway Incidents addresses the need to balance the safety of motorists, responders, and victims with the need to restore traffic flow. The Model Procedures Committee encourages incident commanders to consider the following factors when managing a highway incident:

  • Provide emergency services and remove the traffic blockage as quickly as possible
  • Protect responders (and those in their care) from being struck by moving vehicles
  • Protect motorists, passengers, and cargo from the hazards of the incident
  • Facilitate the movement of emergency response vehicles
  • Facilitate traffic flow past the incident and throughout the region

Highway agencies can achieve many benefits from working with other responding agencies to adopt common guidelines for managing highway incidents. Written guidelines provide a standardized, predictable approach and may be applied routinely. They provide a training tool for responders, offer a baseline for critiques and reviews of incidents, and make the commander's operations more effective. Written guidelines either can reflect strict policies or allow flexibility in managing incidents.

Members of the Incident Management Procedures Committee

  • Gene Chantler, Deputy Chief (ret.), Poudre Fire Authority, Fort Collins, CO
  • K. Craig Allred, ITS Public Safety Program Coordinator, USDOT
  • John Amrhein, Sergeant, San Bernardino (CA) County Sheriff's Office
  • Wayne Bindas, Deputy Chief (ret.), Hartford (CT) Fire Department
  • Ken Brooke, Mitretek Systems, contractor to USDOT ITS Public Safety Program
  • Dave Helman, Office of Operations, Federal Highway Administration, USDOT
  • Bob Neamy, Deputy Chief, Los Angeles City Fire Department
  • Ron Miner, Southeast Regional Business Development Manager, Mission Systems Sector, Northrop Grumman
  • Bob Ricker, Lieutenant, New Jersey
    State Police

Scenario-Based Guidelines

The Model Procedures Guide for Highway Incidents contains a series of scenarios, with an example for each scenario of a complete, systematic organizational structure based on the IMS. The structure is designed to provide the major functions of command, operations, planning, logistics, and finance and administration. Local agencies decide how to provide staffing for standardized tasks.

The committee designed this IMS for use during all types and sizes of highway incidents, from routine mechanical breakdowns and crashes to severe weather and terrorist events. The IMS enables the organizational structure to expand and contract according to the severity and circumstances of the incident, facilitating a smooth transition between single-unit responses and multiagency operations.

The IMS builds the organization from the ground up, adding functional units for new activities. The incident is partitioned into manageable tasks, and the best-qualified response resources are assigned to each need. As the incident grows in complexity, the system maintains a safe span of control and ensures that all activity is conducted under a single chain of command. The IMS ensures the safety of responders, crash victims, and motorists, while responders mitigate the impact of the incident on traffic flow and the surrounding community.

The concepts in the guide were proven effective by emergency service crews, who also fine-tuned the IMS in the field over nearly 30 years, and the American National Standards Institute codified IMS as National Fire Protection Association Standard 1561. Nonemergency responderssuch as transportation, public works, and public health agenciesalso can be incorporated into the IMS organization. The terminology used in the guide was chosen carefully to convey a uniform message to users from all response professions and for all levels of Government.

In addition, the IMS recognizes that all highway incidents are managed under the authority of the agencies that have statutory jurisdiction. Multijurisdictional incidents may be managed under a unified command structure that includes representation from each jurisdiction. Assisting and supporting agencies also participate by contributing resources, onsite agency representatives, and liaison or information channels.

Strategy, Tactics, and Tasks

The guide stresses the importance of following the IMS organizational procedures for small incidents as well as larger ones. The practice and training afforded in the more numerous smaller incidents will ensure smooth operation when larger ones occur.

Even for a simple incidenta car pulled over for a traffic law violationthe guide urges that responders maintain the IMS, with the role of incident commander always filled (in this case, by the sole police officer at the scene). The three levels of the IMS command structure are:

  1. Strategic level: determining the overall direction and goals of the incident
  2. Tactical level: determining the objectives that must be met to achieve the strategic goals
  3. Task level: assigning tasks that will meet the tactical objectives

In the simple, single-unit response, the incident commander determines strategy and tactics and supervises the crew doing the tasks. If the incident becomes more complex and requires more resources, the initial commander requests additional personnel. When a higher-ranking officer or senior supervisor arrives, that individual assumes command and reassigns the original commander. As a situation becomes increasingly complex, the strategic level can expand. The incident command structure could enlarge to a unified command if several departments or jurisdictions are involved, and a level of section leaders could be added, with many people staffing the tactical and task levels below.

Incident management systems can help drivers avoid long traffic delays like this one, caused by an overturned livestock truck on an interstate highway in Pennsylvania.

Establish an IMS First

Because a major incident initially has more tasks than staff resources to accomplish them, the tendency is to jump in and start the tasks immediately rather than establish an IMS. "This is a major error," the guide warns. "The lack of direction will result in confusion and lack of coordination. This increases the risks to emergency personnel and decreases the likelihood of a successful operation."


The IMS creates organizational subcomponents to direct operations in specific geographical areas (for example, sections of a highway) or to manage incident-related functions (such as care of injured). Called divisions or groups, the subcomponents reduce the span of control to smaller, more manageable units. Establishing divisions or groups and assigning them responsibilities early in the incident provides an effective organizational framework to build on. After establishing divisions and groups, the incident commander can concentrate on overall strategy and assign tactical objectives and resources. The supervisors of each division and group manage their assigned resources to complete the tactical objectives, communicating their needs and progress to the commander.

This system reduces overall radio communications, enabling responders to transmit critical messages and enhancing the safety of those on the scene. The supervisors control both the position and function of each of their assigned companies and continuously monitor all hazardous situations and risks to personnel, ensuring safe and effective operations.


Transportation Roles In the IMS

"Emergency services are well-accustomed to using IMS for all types of incidents," says Ken Brooke, principal, Mitretek Systems, a member of the committee. "Transportation is one of the newer participants, but it fits smoothly into the IMS organization."

Among many other specialized resources and skills, transportation resources can provide emergency roadway repair, mass transport of victims, traffic control and management (Traffic Management Centers), assistance setting up dams and dikes or applying absorption materials, and construction and demolition equipment and operators.

Technical specialists from the transportation community can be drawn from transit, airport, pipeline, and rail authorities, plus highway authorities in charge of bridges, toll roads, tunnels, and roadways (State DOTs, departments of motor vehicles, and public works). These agencies have a wide range of training, experience, capabilities, supplies, and apparatus types, but they do not have the sort of operating procedures that emergency service agencies have in placenamely, the practice and experience of setting up an efficient, multiagency, emergency command structure and communications system.

Managing Transportation Resources

During an incident, transportation resources can be managed efficiently by organizing traffic-control strike teams and task forces. Strike teams are groups of up to five units of the same type of resourcefor example, five snowplows. Task forces are groups of up to five units of different types of resources, such as one barricade truck, two patrol cars, one fire engine, and one sign truck.

A single barricade strike team can combine city-, county-, and State-owned barricade trucks. Likewise, a snowplow strike team can include city, county, State, and contract plows.

Traffic-control task forces, each comprising several different resources under a single supervisor, can set up and operate a roadblock, checkpoint, merge, or taper conveniently. One such task force might include a law enforcement unit, two flaggers, a follow-me truck, and a traffic cone truck. Another may include a sign truck, a county barricade truck, two motorist assistance units, and a law enforcement unit.

The guide recommends that incident commanders consider assigning a law enforcement unit with each task force or strike team for two reasons. First, the traffic-control strike team vehicles are large and hard to maneuver, and they do not have the special right-of-way privileges of emergency vehicles. For example, a police escort can assist them in making their way through congestion to the incident scene. Second, although uncontrolled traffic presents a major risk to everyone on the scene, motorists may not obey flaggers who are assigned to control traffic. Often the mere presence of police vehicles is enough to preserve order.

A Sample Scenario

The Model Procedures Guide for Highway Incidents walks responders through several highway incidents, showing responses to changing or escalating situations. Below is a shortened version of one scenario, illustrating a common highway incident and how the command structure typically changes as the incident unfolds.

Stage One

A two-vehicle crash with injuries is reported. Two police department (PD) units, one fire battalion chief, two fire engines, and two emergency medical services (EMS) units are dispatched. Fire Engine 4 arrives first, closely followed by the EMS and police units. The battalion chief is delayed in traffic. The captain of Engine 4 assumes command, provides dispatch with a sizeup report, and asks for an additional fire truck (Truck 3) after learning that the occupants of one vehicle are trapped. He assigns the Engine 5 officer as the extrication group supervisor, with Engines 4 and 5 assigned to extrication. He assigns Medic 40 as medical group supervisor with Ambulances 40 and 41 as his resources. He assigns the corporal in PD Unit 7 as law enforcement group supervisor and assigns PD Unit 8 as his resource.

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Stage Two

Soon, the battalion chief, Truck 3, and the safety officer arrive, as well as a city PD supervisor (PD Unit 4). The incident commander assigns Truck 3 to the extrication group and the safety officer to his command staff. After briefing the battalion chief on the situation, Engine 4's captain transfers command to him. The new commander then reassigns Engine 4's captain as liaison officer to work with the traffic management center (TMC), which has been in contact with dispatch, concerned about the increasing traffic congestion due to the crash. The city PD sergeant is assigned as law enforcement group supervisor and immediately requests two wreckers to remove the vehicles.

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Stage Three

The safety officer determines that the passing traffic is the main hazard to the responders. He also notices that the guardrail was significantly damaged. Although the scene is protected, he sees problems building in the traffic backup, as drivers become frustrated while trying to negotiate the blockage. At the same time, the growing traffic congestion is beginning to stretch the capabilities of the PD units directing traffic. They tell their law enforcement group supervisor that they need more units so they can begin their investigation and prepare reports. The supervisor asks the incident commander for more resources.

Checking with the TMC, the liaison officer learns that the backup is beginning to cause major traffic problems along the arterial, stretching more than a mile in each direction. After checking with the commander, the liaison officer asks for additional support from the TMC. The county DOT tells the TMC that it is sending a maintenance truck and a sign truck, along with a supervisor.

Meanwhile, the extrication group removes the trapped occupants, who refuse transport to a hospital because their injuries are minor. Only a small amount of coolant has leaked from the vehicles, and the crew from Truck 3 covers the pools with absorbent. At this point, the incident commander releases the fire department resources and then transfers command to PD Unit 4.

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Stage Four

After the towing company finishes loading the second vehicle, command is turned over to the DOT supervisor as the law enforcement units leave the scene.

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Stage Five

The remaining units perform repairs and deal with traffic congestion for 2 more hours. When repairs are done and traffic returns to near-normal flow, the incident is terminated, and all remaining units are released.

(Above) An incident management system can help emergency responders, police, firefighters, department of transportation personnel, and towing operators coordinate their responses and clear this overturned truck quickly and effectively.

Write It Down: Plans and Worksheets

"Incident action plans are critical for the rapid, effective control of emergency operations," the guide states.

The guide offers several examples of incident management planning sheets. Action planning starts when the incident commander identifies the strategywhat has to be done. Then the commander or the operations section chief selects the tactics (how, where, and when). An incident action plan also provides for necessary support resources, such as traffic control, transportation vehicles, extrication tools, and law enforcement. The plan is a continuous work-in-progress. Information must be gathered and analyzed so the plan may be modified as needed.

"As an incident escalates from a few agencies to a major operation," Brooke says, "the incident commander may need to track where all the resources are committed on the emergency scene. That's why it's important to use a tactical worksheet."

The guide offers several examples of tactical worksheets designed to help the commander (and divisions and groups) document where resources are committed and what other resources are available, what organizations are participating, and where they are assigned. The sample tactical worksheets also include a template for a sketch of the incident area.

Using a standardized format makes the information more accessible to many parties, including newly arriving commanders. The information on the worksheets is valuable in post-incident analysis
and cost recovery.

Next Steps

The Model Procedures Guide for Highway Incidents is scheduled for publication in summer 2004. Hard copies will be available from Fire Protection Publications, a department of the College of Engineering, Architecture, and Technology at Oklahoma State University, by calling 800–654–4055 or visiting It is also available online at

The new guide will join a series of similar publications, also produced by the same organization, that present recommended ways of applying the IMS to various incident typesfrom the traditional firefighting domains of structural and wild land fires to highly specialized operations involving hazardous materials, structural collapse, and mass casualties.

"After we finalize the guide," says Model Procedures Committee Chairman Gene Chantler, "the challenge will be getting people to use it." Agencies never know when an emergency will strike, or when they may need to participate on a response team.

K. Craig Allred is the ITS public safety program coordinator in the Federal Highway Administration's ITS Joint Program Office in Washington, DC.

For more information about the draft Model Procedures Guide for Highway Incidents, visit