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A highway incident is any non-recurring event (such as a vehicle crash, a vehicle breakdown, or a special event) that causes a reduction in roadway capacity or an abnormal increase in traffic demand that disrupts the normal operation of the transportation system. Most highway incidents are random events that occur with little or no advance warning. They can vary widely in terms of severity, ranging from a minor crash involving a single response agency (such as law enforcement) to a natural disaster or other catastrophe requiring a multi-agency response from multiple jurisdictions and disciplines. Incidents are a major source of congestion on the roadway system and can contribute to problems away from the actual incident scene (for example, secondary crashes caused due to unexpected congestion).

Traffic incident management (TIM) is defined as the coordinated, preplanned use of technology, processes, and procedures to reduce the duration and impact of incidents, and to improve the safety of motorists, crash victims, and incident responders. Specifically, TIM involves the use of technology, procedures, and processes to accomplish the following:

  • Reduce the amount to time to detect and verify that an incident has occurred,
  • Shorten the time required for appropriate response personnel and equipment to respond to the scene,
  • Facilitate the management of response apparatus and personnel on site so as to minimize the amount of capacity lost due to the incident and the response equipment,
  • Reduce the amount of time required to clear the incident from the travel lanes
  • Provide for the rapid notification of travelers upstream of the incident so as to encourage a reduction in traffic demand entering the incident area and to reduce driver frustration.

Planning and Coordinating With Incident Response Agencies

Incident management programs are successful when they are built on a foundation of cooperation and collaboration. When planning or organizing a construction project, it is essential that work zone planners and construction personnel coordinate with the incident responders in the area. This includes identifying and meeting with agencies to discuss current response policies, procedures, and practices.

Table 1 shows an example of typical incident responder who may perform key response functions at an incident scene. On minor construction and maintenance projects, work zone planners and contractors may only need to coordinate with a few of these stakeholders (such as fire and police agencies); however, on more complex projects, it may be necessary to coordinate with all of these stakeholders to develop an implementable incident management plan.

Table 1. Example Roles and Responsibilities of Key Incident Responders

Typical Traffic Incident Management Functions

Traffic Incident Management Responders

Emergency Dispatch (911 Center)


Emergency Medical Services (EMS)


Law Enforcement

Medical Examiner/ Coroner

Towing & Recovery

Transportation/ Public Works


Transit Operator

Metropolitan Planning Organization

Transportation Management Center

Construction Contractor

Quick Clearance Policies









Detection / Notification of Incident








Dispatch of Incident Management Assets / Emergency Responders










Public Safety at Incident Scene











Fire Suppression













Rescue/Extraction of Victims












Triage, Treatment, and Transport of Crash Victims













Hazardous Material Cleanup and Disposal












Secure / Stabilize Incident Scene












Traffic Control / Road and Lane Closures /Openings










Crash/Fatality Investigation












Removal of Wrecked or Disabled Vehicles











Debris Removal / Spilled Fluid Removal













Activation / Traffic Management of Diversion Routes










Stabilization and Repair of Roadway Infrastructure












Public Notification










• represents those agencies that may be involved in a discussion of agency responsibilities in local incident response

The Incident Command System and Unified Command

To improve the nation’s preparedness to response to incidents of all magnitudes, the Department of Homeland Security has developed the National Incident Management System (NIMS). NIMS was developed so responders from different jurisdictions and disciplines can work together better to respond to natural disasters and emergencies. Part of the NIMS structure involves the use of the Incident Command System (ICS). ICS is a systematic tool used for the command, control, and coordination of an emergency response.9 It is designed to facilitate agencies working closely together through the use of common terminology and operating procedures to control personnel, facilities, equipment, and communications at a single incident scene. The guiding concepts and principles of ICS are as follows:

  • Most incidents are managed locally by local agencies to provide a coordinated, cooperative response.
  • The field command and management functions should be performed in accordance with a standard set of ICS organizations, doctrine, and procedures.
  • ICS is modular and scalable so that responses can be adapted as situation, technology, size, and complexity of the incident changes.
  • All component of the response are managed interactively in a coordinated manner.
  • ICS establishes common terminology, standards, and procedures that enable diverse organizations to work together effectively.
  • Incidents are managed by objectives, which are measureable and begin at the top and are communicated throughout the entire response.
  • Implementation of ICS should have the least amount of disruption of existing systems and processes as possible.
  • ICS should be user friendly and be applicable across a wide spectrum of emergency response and incident management disciplines.

The overwhelming majority of highway incidents do not require the formal implementation of the ICS.9 Instead, most highway incidents involve just law enforcement or highway personnel and a tow truck. In these situations, there is usually no need for the organization and command structure of the ICS. Only when traffic incidents are large and more complex does the ICS become necessary because of the need for multiple responders from multiple agencies. In these situations, it is critical for work zone planners and construction personnel to understand what the ICS is and how emergency responders use the ICS to manage all types of incidents, not just highway traffic incidents.

The term Unified Command (UC) is used to define the application of ICS when there is more than one agency with incident jurisdiction or when an incident crosses political jurisdictions. In situations where an incident crosses multiple jurisdictions, or in the case where multiple agencies have jurisdiction over the same incident (for example, a wreck with injuries or fatalities), unified command allows all agencies that have statutory authority for an incident to jointly participate in the development of the overall response strategy.
For more information on the ICS, and its application to highway incidents, the reader is encouraged to review Simplified Guide to the Incident Command System for Transportation Professionals. 9

Assessing the Need for Traffic Incident Management in Work Zones

The process to be used to develop a TIM program for a particular construction or maintenance project is not unlike the process used to develop a traditional incident management program. What is different about the TIM program for a construction or maintenance program is who commonly initiates the development process – the construction project manager or the contractor. This process needs to begin at the very early planning stages of the project, oftentimes well before traditional incident responders are aware that the project is going to be let.
Work zone and construction planners need to first assess if there is a need to implement special incident management procedures with a particular work zone. Questions that transportation agencies and work zone planners should ask in determining whether or not a particular work zone project needs improved TIM responses include:10

  • Will this project impact emergency response in this segment of highway?
  • Are there access issues for responding to incidents within the work zone?
  • If an incident closes the highway in one or more directions, how will traffic be re-routed?
  • Are there strategies to minimize project impacts on response agencies?
  • Are there strategies to minimize incident impacts on the public?
  • Are there procedures that would enhance traffic incident clearance and safety?
  • What equipment would improve emergency response and management during construction? Is it available? Where is it located?
  • How will project personnel coordinate and assist emergency responders?

The Planning Process

Figure 2 shows steps involved in developing a TIM program for an individual construction or maintenance project deemed to be in need of special procedures and practices to mitigate the impact of traffic incidents in the work zone. Each step is discussed in detail below.

Figure 2. Process for Planning Traffic Incident Management for Highway Work Zones (Adapted from 10)

Figure 2. Process for Planning Traffic Incident Management for Highway Work Zones

Assessing Existing Traffic Incident Management Processes and Procedures

In many locations throughout the United States, comprehensive incident management programs and processes already exist; therefore, the first step in developing a TIM program for a specific construction or maintenance project is to determine and assess what incident management processes and procedures already exist in the area where the work zone will be in effect. In many cases, it may be wasteful and counterproductive to develop new and different response procedures. Work zone planners need to first check to see if the project lies within the boundaries and jurisdiction of any existing incident management program. If it does, work zone planners and contractors need to coordinate with appropriate response and traffic operations personnel to determine if the existing processes and procedures are adequate for the project. Together, these agencies can identify those changes, additions, and modifications to the existing procedures and responses that may be needed to accommodate the project. In the situation where existing TIM practices and procedures are already in place, at a minimum, work zone planners should contact appropriate response agencies in the corridor to discuss issues and concerns about managing incidents in the proposed work zone and agree upon the procedures and strategies that will be implemented to support TIM in the work zone. On more complex projects, it is necessary for the work zone planner, project administrators, and construction personnel to become active partners in the existing incident management program for the duration of the project. On projects with multiple phases, it may be necessary to develop a plan for each phase of the project.

Identifying Incident Management Stakeholders

If the proposed project lies outside the jurisdiction of any existing TIM program, it may be necessary for work zone planners and contractors to identify, develop, and deploy TIM strategies that are appropriate for the type and level of work zone. In most regions, multiple agencies are involved in the TIM process. At a minimum, work zone planners and contractors should meet with key incident response agencies to discuss how the project will impact TIM responses. The following is a list of potential agencies and organizations that are traditionally involved in the development of TIM programs in a region:

  • Federal, state, and local transportation agencies
  • State and local law enforcement personnel
  • Public and volunteer fire and rescue agencies
  • Regional, county, or local 911 dispatch
  • Towing and recovery providers
  • Emergency medical service providers
  • State and local hazardous material recovery personnel
  • Media, and
  • Other response personnel (as defined by the project area), including state and local offices of emergency management, coroner’s office, etc.

Work zone planners and contractors must be aware that multiple agencies may have jurisdiction over incident responses within the limit of a construction project. It is not uncommon for multiple police, fire and rescue, and emergency service providers to have incident management responsibilities on a given highway. Work zone planners need to make sure that all appropriate incident responders are identified for any given project.

Establishing Incident Response Goals and Objectives for the Work Zone Project

After becoming familiar with the capabilities and structure of current incident management programs that may be impacted by a work zone project, the next step in the process is to establish goals and objectives (or response targets) for the incident responders in a work zone. Goals define the desired effects of agencies in responding to incidents in the work zone while objectives define discernible (or measurable) outcomes that show how a particular goal is being met by one or more strategy.5 Table 2 shows common goals and objectives used in determining incident management response procedures and strategies in the work zone.

Table 2. Common Goals and Objectives Used in the Planning of Work Zone Incident Management Programs



Improve work zone mobility

  1. Minimize detection and verification times
  2. Minimize notification times among response agencies
  3. Minimize the time needed to transport equipment to an incident location
  4. Minimize incident investigation time
  5. Minimize number of closed lanes
  6. Minimize the length of exposure
  7. Minimize road and lane closure times
  8. Minimize motorist delay
  9. Minimize traffic demand at and approaching the scene without causing severe impacts on surrounding streets
  10. Provide data for automated incident detection
  11. Provide temporary surveillance system for high incident locations
  12. Improve coordination with the diversion route’s traffic control system to carry increased traffic volume

Improve work zone safety

  1. Minimize the response time of emergency medical services
  2. Minimize the time necessary to identify the characteristics of hazardous material cargo
  3. Minimize traffic hazards near the incident location
  4. Maximize the safety of responders and travelers
  5. Exercise proper and safe on-site management of personnel and equipment
  6. Improve personnel training for site response
  7. Improve personnel training for response to hazardous material incidents

Efficiently and effectively use resources

  1. Minimize the personnel cost associated with incident management
  2. Minimize the cost to motorists of incident related delay
  3. Maximize the use of existing communication resources
  4. Protect the roadway and private property from unnecessary damage during the removal process
  5. Develop resource sharing agreements

Improve inter-agency cooperation

  1. Maximize understanding of agency perspectives and responsibilities
  2. Maximize information sharing among agencies
  3. Maximize coordination between response and transportation agencies
  4. Establish inter-agency field communications
  5. Employ advanced communication technologies among agencies
  6. Develop administrative coordination among agencies
  7. Form consensus among agencies

Improve public perception

  1. Educate drivers to improve their reactions to traffic incidents
  2. Provide timely, accurate information to the public that enables them to make informed decisions
  3. Provide motorists with information about the cause of their delay to minimize their level of frustration with the road system
  4. Adequately inform motorists of the location and scope of incidents
  5. Improve the public image of the response agencies
  6. Foster wide dissemination of real-time traffic information

Source: Guidebook on Incident Management Planning in Work Zones5

It should be noted that different stakeholders involved in the project may have different goals and objectives. For example, the prime contractor may want to limit costs so as to maximize profits. The agency project manager may desire to complete the project on-time and within budget while avoiding major cost overruns or change orders. Incident responders may want to minimize their response times while ensuring responder safety. Traffic operators may want to minimize the amount of disruption to normal traffic flow. Oftentimes, the goals and objectives of individual agencies conflict with one another. It is imperative that all agencies responsible for responding to incidents within the limits of the area impacted by the construction project be involved in setting the goals and objectives and in determining which strategies are best for responding to an incident in the work zone. Keep in mind that effects of the construction project on traffic operations may extend well beyond the actual limits of the construction project.

Determining Appropriate Levels of Response

Agencies have at their disposal a large number of strategies, technologies, techniques, and procedures for providing incident management in work zones; however, not all are appropriate for every work zone situation or incident scenario. Each strategy, technology, and procedure needs to be evaluated within the context of project needs and duration, the infrastructure requirements, the level of cooperation and coordination between incident responders, and the costs and perceived effectiveness of the strategy. Some strategies are needed to provide a solid foundation for other strategies, while other strategies are more appropriate when the work zone project is expected to impact traffic operation for extended periods (years, for example). Agencies need to carefully evaluate each strategy and incident scenario and determine the appropriate level of response for each type of incident. Agencies also need a realistic assessment of the likelihood that an incident of major severity may occur when the work zone is in effect.
Agencies need to keep in mind that all incident situations are not the same and that not all incidents require or mandate the same level of response. Recognizing this fact, the Manual on Uniform Traffic Control Devices 11 divides incidents into three general classes based on duration, each of which has unique traffic control characteristics and needs. These classes are as follows:

  • Major – typically traffic incidents involving hazardous materials, fatal traffic crashes involving numerous vehicles, and other natural or man-made disasters. These traffic incidents typically involve closing all or part of a roadway facility for a period exceeding 2 hours.
  • Intermediate – typically affect travel lanes for a time period of 30 minutes to 2 hours, and usually require traffic control on the scene to divert road users past the blockage. Full roadway closures might be needed for short periods during traffic incident clearance to allow traffic incident responders to accomplish their tasks.
  • Minor – typically disabled vehicles and minor crashes that result in lane closures of less than 30 minutes. On-scene responders are typically law enforcement and towing companies, and occasionally highway agency service patrol vehicles. Diversion of traffic into other lanes is often not needed or is needed only briefly. It is not generally possible or practical to set up a lane closure with traffic control devices for a minor traffic incident. Traffic control is the responsibility of on-scene responders.

Agencies can use these general criteria for classifying incident levels as a beginning point for determining appropriate levels of responses. However, these criteria should be refined to be consistent with agency goals and objectives.

One underlying principle of the ICS is that it allows responses to be scaled to the level that is appropriate for the situation and existing conditions. An initial small response can be transitioned to a large, multi-agency operation with only minimal adjustment for the agencies involved.9 ICS provides a structure that allows responses to expand and adapt the real-time conditions that exist in the field.

Identifying and Evaluating Detection, Response, and Clearance Strategies

Once the appropriate level of response has been determined for the work zone, the next step in the process is to identify and evaluate candidate strategies for detecting, responding to, and clearing incidents from the roadway. Chapter 5 lists a number of strategies commonly used by agencies to improve incident detection, enhance responses, and promote rapid clearance of incidents in work zones. Advantages and disadvantages of each strategy have been provided along with reference information to determine more details about strategies.

In determining which incident management strategy is appropriate for a particular work zone, agencies may want to consider the following:2

  • Facility type (freeway, highway)
  • Area type (urban, rural)
  • Project length
  • Project duration
  • Multiple construction stages/phases
  • Traffic volume
  • Capacity reductions
  • Expected delays
  • Crash rates
  • Percentage of trucks
  • Available detour route(s)
  • Available alternative travel modes
  • Community factors (public exposure, business impacts, and residential impacts)

It is also critical that agencies examine how incidents will be managed during all phases of the construction project. Agencies need to assess how changes in access restrictions, capacity reductions, and lane management techniques (such as shoulder usage) impact each strategy.

Developing an Incident Management Response/Action Plans

After determining which strategies are appropriate for a particular work zone, agencies then need to develop criteria and conditions for when and how these responses should be executed. This is typically called a response or action plan. The response or action plan lays out the conditions and criteria for what types of responses are needed for different levels of incidents that might occur in the work zone.
Table 3 shows an example of a response plan developed by the Colorado Department of Transportation for the T-REX construction project in Denver.12 The T-Rex construction project was a multiple year effort to reconstruct Denver's I-25/I-225 Southeast Corridor and to extend the region's light rail system. As shown in Table 3, different response actions have been defined for each level of incident. The incident levels are defined based on the extent and duration of the anticipated impacts on traffic operations on the roadway. The levels are not intended to be hard and fast “thresholds” for defining incident responses, but are intended to provide responders with an initial assessment of the type and magnitude of response that might be needed to manage the incident.

Table 3. Example of Recommended Incident Response Plan Used in the T-REX Construction Project by the Colorado Department of Transportation


Impact to Roadway

Action to be Taken


Impact to traveled roadway estimated to be less than 30 minutes with no lane blockage.

Or –

Impact to traveled roadway is estimated to be less than 30 minutes with lane blockages

  • Follow agency protocols
  • Contact the CDOT Traffic Operation Center (TOC)

TOC Action:

  • Contact CDOT Region 6 Maintenance Supervisor
  • Consider activating selected variable message signs (VMS)


Impact to traveled roadway estimated to be greater than 30 minutes, but less than 2 hours with lane blockages, but not a full closure of the roadway

  • Establish Incident Command
  • Consider designating staging areas
  • Contact the CDOT TOC

TOC Action:

  • Consider implementing alternate routes
  • Update CDOT and T-REX Web sites
  • Activate highway advisory radio (HAR)and signs
  • Place messages on dynamic message signs (DMS)
  • Consider activating the following VMS:

                [List of VMS devices to be activated]

  • Fax out advisories to Level 2 contacts
  • Contact the following:

                [List of responders to be activated]


Congestive impact to traveled roadway is estimated to be greater than 2 hours or roadway is fully closed in any direction.

  • Establish Command Center or Post
  • Coordinate with CDOT to implement alternative routes
  • Consider designating staging areas
  • Contact CDOT TOC

TOC Action:

  • Update CDOT and T-REX Web sites
  • Activate HAR and signs
  • Place messages on DMSs
  • Consider activating VMS:

                [List of VMS devices to be activated]

  • Fax out advisories to Level 2 and Level 3 contacts
  • Request METS broadcast notification – update to
  • Contact the following:

                [List of responders to be activated]

  • Contact signal jurisdictions on alternate routes.

As part of developing a response or action plan, agencies may also want to develop procedural guidelines for how and when a certain response or incident management function should be performed in a work zone. The following lists topics where procedural guidelines may be needed for incidents that occur in work zones:

  • Notifying other incident responders
  • Managing the scene
  • Moving damaged or disabled vehicles
  • Closing and openings lanes
  • Implementing alternative routes
  • Using emergency flashing lights
  • Parking and staging of response apparatus
  • Disseminating information to travelers and the media

Distributing the Response/Action Plans to Response Agencies

Once the response plans have been developed, the next step in the process is to distribute the response plans to the appropriate response agencies. Because the response plans are usually developed in cooperation and collaboration with emergency responders, dissemination of the plan to the incident responders often occurs naturally, but it is important for traffic operators to ensure that the response/action plan is disseminated to the appropriate response and field personnel. As part of the plan development process, stakeholders should also discuss methods and procedures for distributing and disseminating the response plan to appropriate personnel within their organization—both at the administrative and field personnel levels.

Providing Training

Training is often an overlooked, but important aspect of developing and implementing a TIM plan for work zones. Most incident responders are well versed on how to respond to incidents during normal operations; however, very few responders have experience responding to an incident and establishing lane closures inside the constraints of a work zone. Transportation agencies should work with local incident responders to develop field exercises that allow responders to become familiar with the issues and constraints associated with working in a work zone environment.

In addition to field exercises, transportation agencies and incident responders should also get together prior to the beginning of the actual work activities to ensure that response procedures are practical and appropriate. Agencies should not assume that just because a response or action plan is in place, it works flawlessly the first time it is needed. It is essential that procedural guidelines, such as notification procedures, be exercised prior to the beginning of the construction project so that rough spots or limitations in the processes are identified and corrected prior to the construct project actually beginning.

Public education is also another critical training function that needs to occur prior to the actual groundbreaking of a construction project. Agencies need to develop a comprehensive public education program that informs the public of what is being done to address traffic issues associated with the project. If “Move-it” laws or quick clearance policies are being implemented for the first time in association with a construction project, the public needs to be educated about what these laws mean and why they are important. If these laws already exist, agencies may want to consider implementing a public education program that reminds the traveling public that these laws exist and are critical to the success of the construction program.

Updating the Incident Management Response/Action Plans

A critical aspect of planning for TIM in work zones is ensuring that emergency response procedures and practices remain valid through all phases of construction. Agencies should also plan to meet routinely to ensure that the important elements of the plan remain valid and up-to-date. On large construction projects, incident responders, transportation agencies, and construction personnel should meet routinely through the life the project to review actual responses to incidents that have occurred during the project and update response and communication plans as needed. Response plans often need to be updated and/or revised as conditions, lane closures, and access to the work zone changes. It is essential that incident responders be notified when new conditions might impact response times or access to the site.

Furthermore, response plans may need to be revised based on feedback from the public, agency decision-makers, and field personnel. If any part of the response plan or program is revised, it is critical that all responding agencies receive notification of how the established response procedure or access needs have changed. Likewise, incidents that damage the pavement or other infrastructure within the work zone need to be communicated to work zone traffic planners as these may impact or change the construction sequences in the work zone. Good two-way communication between incident responders and construction personnel is critical.