Photos of cars on freeway, speeding sign

Freeway Management and Operations Handbook

Chapter 10 – Traffic Incident Management

10.1 Introduction

A traffic incident is a non-recurring event that causes a reduction of roadway capacity or an abnormal increase in demand. In most metropolitan areas, traffic incident-related delay (not including other non-recurring delay caused by weather, work zones, etc.) is estimated to account for between 25 and 30 percent of total congestion delay. In smaller urban areas, it can account for an even larger proportion (Reference 1). Although the problems most often associated with traffic incidents are congestion and associated traveler delay, increased fuel consumption, and reduced air quality, the most serious problem is the occurrence of secondary crashes. Another related issue is the danger posed by traffic incidents to response personnel serving the public at the scene.

Although traffic incidents constitute only a portion of all public safety and emergency management incidents, the general principles for effective management of all types of incidents are comparable. Effective traffic incident management (TIM) programs, like other incident management programs, feature ongoing, actively administered, organizationally structured, interjurisdictional, multi-disciplinary and fully documented procedures. More than merely an assemblage of technologies and activities, successful TIM programs must be fully integrated into the culture of the stakeholder institutions.

For example, the Washington state program features high level institutional coordination documented in the Joint Operations Policy Statement (JOPS). This was signed on February 13, 2002, by the Washington State Patrol and the Washington State DOT, and makes a matter of policy the extensive coordination between the two agencies on a number of matters, including traffic incident response. One of the stated goals is the clearance of all incidents within 90 minutes.

Traffic incident management is the systematic, planned, and coordinated use of human, institutional, mechanical, and technical resources to reduce the duration and impact of traffic incidents, and improve the safety of motorists, crash victims, and traffic incident responders. Effectively using these resources can also increase the operating efficiency, safety, and mobility of the highway. This results from reducing the time to detect and verify a traffic incident occurrence; implementing the appropriate response; safely clearing the incident; and managing the affected flow until full capacity is restored (Reference 1).

A traffic incident management program is a logical, structured, and integrated set of traffic incident management activities tailored to a specific geographic area. It includes policies, strategies, and technologies integrated into a multi-agency, multi-jurisdictional environment aimed at reducing the occurrence and impact of traffic incidents. To be successful, a TIM program must be on-going and actively managed. The TIM program should be developed and managed in conjunction with the area's freeway management and operations program. The organization of the TIM program and the operational responsibilities of its participants should fit into the organization structure of the region, recognizing the existing assignment of traffic incident management activities and addressing gaps and overlaps in those assignments.

10.1.1 Purpose of Chapter

The Traffic Incident Management Handbook (Reference 1) treats traffic incident management in depth and is considered the primary reference on the subject. This chapter summarizes that reference, highlighting the essential elements of an effective traffic incident management program. References 2, 3, 4 and 11 should also be consulted.

10.1.2 Relationship to Other Freeway Management Activities

Traffic incident management is often a major element – if not the cornerstone – of a freeway management and operations program. The ultimate success of a traffic incident management program depends on the on-going collaboration and coordination (as discussed in Chapter 2) among the various entities involved. Several ITS components can support and enhance a traffic incident management program, including surveillance (Chapter 15) to detect and verify incidents, disseminating information to travelers regarding the resulting congestion and alternatives (Chapter 13), improving response via the coordination afforded by a Traffic Operations Center (Chapter 14), as well as the real-time sharing of information (Chapter 16) among the affected agencies. Additionally, the various activities and coordination needs for traffic incident management parallel those associated with special event management (Chapter 11) and emergency / evacuation management (Chapter 12).

Traffic incident management is a critically important piece of a freeway management program, and should be considered in all stages of developing and implementing a freeway management and operations program (Chapter 3). Moreover, like all programs and activities that are intended to improve the operation of the transportation network, the performance of a traffic incident management program should be regularly monitored and assessed (Chapter 4), potentially resulting in changes and refinements.

10.2 Current Practices, Methods, Strategies, and Technologies

10.2.1 Overview

A traffic incident is a non-recurring event on or near the roadway that causes a reduction of roadway capacity or an abnormal increase in demand. Such events include traffic crashes, disabled vehicles, spilled cargo, and highway maintenance and reconstruction projects. Non-emergency events (e.g. ball games, concerts, festivals) are considered planned special events and are discussed in Chapter 11 (Planned Special Event Management) and Reference 6. Emergencies such as natural disasters and terrorist attacks are also unplanned; and they can cause a reduction of capacity or an abnormal increase in demand. But their impacts and management requirements extend well beyond the roadway as discussed in Chapter 12, Freeway Management During Emergencies and Evacuations.

Traffic incidents, such as crashes, spills, and vehicle disablements, vary widely in scope and severity. To mitigate these nonrecurring events in the safest, quickest, and most cost-effective manner requires:

  • A traffic incident management toolbox of integrated policies, strategies, and technologies (Reference 1), thereby reducing the time to detect and verify a traffic incident occurrence;
  • Implementing the appropriate response;
  • Safely clearing the incident; and
  • Managing the affected flow until full capacity is restored.

Quick clearance policies and freeway service patrols target minor traffic incident occurrences (Reference 5) but more recently have been applied to aggressive removal of heavily damaged vehicles and cargo (shoving, dragging, scooping, bulldozing), prohibitions against in-lane off-loading of cargoes, towing and recovery practices, and crash investigations. Major incidents like a severe crash or spill (especially hazmat) require a more intensive traffic incident management effort usually involving a cooperative, multi-agency approach. In essence, the unpredictable and dynamic nature of traffic incidents mandates the planning and coordination of a wide range of traffic incident management tools.

The goal of the Traffic Incident Management Handbook (Reference 1) is to assist agencies responsible for traffic incident management activities on public roadways to improve their programs and operations. Agencies typically responding to highway incidents include:

  • Law Enforcement
  • Fire and rescue
  • Towing and recovery
  • Emergency medical services (EMS)
  • Environmental Protection (for HAZMAT incidents)
  • Transportation agencies

The intended audience for this chapter and the Traffic Incident Management Handbook is primarily managers who are responsible for traffic incident management program development; and field practitioners who are responsible for providing program services on a day-to-day basis. As such, the Traffic Incident Management Handbook provides guidance from two perspectives – first, as a process to follow in establishing a new traffic incident management program or in improving an existing one; and second, through the identification of tools and strategies that can enhance field operations.

10.2.2 Benefits

Reduced traffic incident duration has proven the greatest contributor to the benefits of a traffic incident management program. Reductions in duration can be achieved by:

  • Reduced detection and verification time
  • Timely and appropriate response
  • Rapid clearance
  • Managed recovery (advising upstream motorists of an upcoming problem or directing entering motorists to remain on a parallel route)

Benefits of an effective program are both quantitative and qualitative. The quantitative benefits include:

  • Increased survival rate of crash victims
  • Reduced delay
  • Improved response time
  • Improved air quality
  • Reduced occurrence of secondary incidents
  • Improved safety of responders, crash victims and other motorists
  • Reduced recovery time

Qualitative benefits include: enhanced traveler information services, increased driver warning capabilities, improved coordination and cooperation of response agencies, improved public perception of agency operations, and reduced driver frustration.

10.2.3 Key Considerations During Freeway Management Program Development

The Traffic Incident Management Handbook (Reference 1) defines an 8-step process for implementing a successful traffic incident management program. This process, summarized below, contains many of the key elements for establishing a freeway management program as discussed in Chapter 3.

A Traffic Incident Management program needs to be facilitated (but not owned) by a lead agency that can provide staff and resources to do so. The program itself must be multi-agency and multi-disciplinary and must continuously, actively and professionally engage all public and private sector program partners.

Regardless of what process is used for developing a traffic incident management program, it is essential that traffic incident management be coordinated with all other elements of the broader freeway management program, and that overall performance of the transportation network be considered.

  • Identify Stakeholders: Critical to the success of a traffic incident management program is the development of a cooperative spirit and consensus among the various stakeholders. Therefore the first step is to identify the relevant stakeholders, such as state, city, and county departments of transportation, Metropolitan Planning Organizations (MPOs), emergency preparedness organizations, emergency medical services, fire departments, state and local law enforcement, transit operators, commercial transportation firms, environmental protection, maintenance, towing operators, major employers, user groups, media, elected officials, policy makers and others specific to the region. Once these stakeholders commit to establishing a traffic incident management program, they can sponsor a traffic incident management Task Force that meets periodically to guide and enhance the program. It has often been said that traffic incident management primarily consists of assembling the involved stakeholders together in an open and non-confrontational atmosphere; the stakeholders will then collectively design their own unique and effective program.
  • Define the Problem: Before identifying, much less selecting a solution, a clear understanding of the severity, impacts, and locations of incident-related problems is required. Problem definition can be accomplished through a combination of data collection, data compilation, brainstorming, and constructive critiques of existing practices. In addition to considering responder activities, responsibilities, and roles in assessing the current practices, it is also important that the Traffic Incident Management Task Force consider the legal and policy environment in which incident management is carried out.
  • Set Goals and Objectives: The Traffic Incident Management Task Force should next establish guiding principles for program development. These "guiding principles" most often take the form of a mission statement, backed up by goals and objectives and based on the identified problems. Simply stated, goals and objectives describe what the program is designed to accomplish. Goals and objectives need to be multi-agency in scope; not merely the goals and objectives of individual agencies. Goals reflect long-term aspirations, and may include: reduce secondary incidents, increase safety for responders, increase and improve use of alternate routes, reduce liability for responding agencies. Objectives typically define the specific, often measurable, level of performance that would be required to progress toward a given goal. Objectives could include: decrease detection times, improve response times, increase motorist information, improve clearance procedures, decrease number of lanes closed, and decrease road and lane closure times.
  • Develop Alternatives: Traffic incident management programs consist of many individual practices, tools and infrastructure elements. Based on the goals and objectives, the group can develop alternatives to combine available traffic incident management tools and techniques into program packages for evaluation. These packages can include those defined in the ITS National Architecture, along with those in Reference 1. In addition to ensuring that the techniques developed are appropriate in terms of covering each of the functional areas of incident management, it is also important that they be suited to the level of interagency coordination that has been established, or that is feasible.
  • Evaluate and Select Alternatives: The developed alternatives can be evaluated using high-level estimates of costs, expected benefits of each alternative, and prioritization. Successful programs have often used a building-block approach, first initiating low-cost components to demonstrate the benefits of traffic incident management activities. Greater support may then become available for more capital-intensive alternatives. Both short- and long-term strategies can be formulated. Alternatives can then be assigned priorities based on Task Force consensus, or more rigorous cost-benefit studies can be used.
  • Implement Alternatives: It is at the point of implementation that mechanisms for resolving many of the issues of incident management must be developed. These issues may include: funding sources, jurisdictional boundaries, operational responsibilities, joint training, field communications, on-site command and approval of alternate routes. One mechanism for formalizing understandings among agencies and jurisdictions is an interagency or inter-jurisdictional agreement. The number, formality, and content of these agreements needed are a function of the specific needs and operating environment of a given area.
  • Reevaluate Alternatives: Traffic incident management is an ongoing process, one that must take into account changes in the local operational, technological, political, and funding environment. Effective program evaluation and the subsequent revaluation of alternatives to refocus or refine an exiting system require the routine collection of appropriate data (e.g., detection time, response time, clearance time, delay and costs). Regular data collection allows program managers to assess the effectiveness of their efforts, to identify areas for improvement, to demonstrate the benefits provided by the program, and to support requests for additional resources. Regular debriefings have also proved effective in continuously reevaluating traffic incident management alternatives.
  • Refine the System: To continuously improve and adapt a traffic incident management program, effective feedback is needed both from upper management and field-level personnel. Genuine communication and coordination on both levels will continue to improve the traffic incident management process, adapt to the area's changing needs and meet the needs of the participating agencies, affected jurisdictions and the motoring public.

In addition to securing broad stakeholder participation from the relevant agencies and jurisdictions, it is also important to ensure that an adequate amount and the appropriate type of public outreach are pursued. Public outreach serves two primary functions: to make the public aware of the value of incident management, leading to generalized public support; and to help the public better understand how their actions, such as moving drivable vehicles out of traffic, and providing good information in reporting incidents, can support effective incident management (1). Traffic Incident Management Program Framework

Reference 3 presents a framework for developing traffic incident management programs as summarized in Figure 10-1. This process includes the previously defined steps but adds additional focus on stakeholder involvement.

chart describing the three phases of program concepts and methods for organizing and sustaining incident management programs

Figure 10-1: A Framework for Organizing and Sustaining Incident Management Programs (Reference 3) D Traffic Incident Management Self-Assessment

With respect to the next-to-last step identified in Reference 1 (i.e. "reevaluate alternatives"), FHWA has developed a self-assessment tool to assist in this reevaluation process. The Traffic Incident Management (TIM) Self-Assessment tool (Reference 8) is designed to:

  • Allow local stakeholders to assess how well they manage traffic incidents and identify areas for improvement.
  • Allow FHWA to assess, at a national level, the needs identified by practitioners and develop program initiatives to address those needs
  • Give FHWA a national program metric to gauge overall progress in traffic incident management.

The TIM Self-Assessment is a tool to be used by state and regional program managers to assess their achievement of a successful multi-agency program to manage traffic incidents effectively and safely. The tool also provides a method to assess gaps and needs in existing multi-agency regional and statewide efforts to mitigate congestion caused by traffic incidents. The TIM self-assessment is not intended as a one-time exercise, but should be conducted on an annual or biennial basis. This will provide a consistent measure of program improvements and allow for continual refocusing of resources to those areas needing them most.

The TIM Self-Assessment consists of a series of questions (summarized in Table 10-1) designed to allow those with traffic incident management responsibilities to rate their performance in specific organizational and procedural categories – specifically, Program and Institutional Issues, On-Scene Operations Issues, and Communications and Technology Issues. The questions in each of these areas address the essence of good traffic incident management programs based upon more than ten years of knowledge and experience gained nationwide. Each question is scored from 0 (no progress in this area) to 4 (outstanding efforts).

Table 10-1: Traffic Incident Management Self-Assessment Questions (Reference 8)

1 – Program and Institutional Issues

Does your TIM program:

  • Have multi-agency, multi-year strategic plans detailing specific programmatic activities to be accomplished with appropriate budget and personnel needs identified?
  • Have formal interagency agreements on operational and administrative procedures and policies?
  • Have field-level input into the plans ensuring that the plans will be workable by those responsible for their implementation?
  • Have formalized TIM multi-agency administrative teams to meet and discuss administrative policy issues?
  • Hold regular meetings of the TIM administrative team?
  • Conduct training through simulation or "in-field" exercises?
  • Conduct post-incident debriefings?
  • Conduct planning for "special events" – (a) construction and maintenance; (b) sporting events / concerts / conventions / etc.; (c) weather-related events; (d) catastrophic events?
  • Have multi-agency agreements on what measures will be tracked and used to measure program performance?
  • Have agreed upon methods to collect and analyze / track performance measures?
  • Have established targets for performance in: a) response and b) clearance?
  • Conduct periodic review of whether or not progress is being made to achieve targets?

2 – Operational Issues

Does your TIM program:

  • Have established criteria for what is a "major traffic incident" – traffic incident levels or codes?
  • Identify high-ranking agency members available on 24/7 basis to respond to a major incident?
  • Have a pre-identified (approved) contact list of resources (including special equipment) for traffic clearance and hazardous materials response?
  • Have the response equipment pre-staged for timely response?
  • Train all responders in traffic control procedures?
  • Utilize on-scene traffic control procedures for various levels of incidents in compliance with MUTCD?
  • Utilize traffic control procedures for the end of the traffic incident queue?
  • Have mutually understood equipment staging and emergency lighting procedures on-site to maximize flow past a traffic incident while providing responder safety?
  • Utilize the Incident Command System?
  • Have specific policies and procedures for fatal accident investigation?
  • Have specific policies and procedures for hazardous materials response?
  • Have quick clearance policies?
  • Have a pre-qualified list of available and contracted towing and recovery operators (to include operators' capabilities)?
  • Use motorist assist service patrols?

3 – Communication and Technology Issues

Does your TIM program:

  • Have a two-way interagency voice communications system allowing for direct on-site communications between incident responders?
  • Provide data and video information transfer between agencies and applications (TMC-CAD integration)?
  • Use Traffic Management Center(s) to coordinate incident notification and response?
  • Have a developed technical infrastructure for surveillance and rapid detection of traffic incidents?
  • Have specific policies and procedures for traffic management during incident response (i.e. signal timing changes, opening/closing of HOV lanes/ramp metering)?
  • Have the ability to merge/integrate and interpret information from multiple sources?
  • Have a real-time motorist information system providing incident-specific information?
  • Provide motorists with travel time estimates for route segments?

10.2.4 Relationship to National ITS Architecture

The traffic incident management market package, as defined in the National ITS Architecture (Reference 7), treats both unexpected incidents and planned events so that the impact to the transportation network and traveler safety is minimized. The market package includes traffic incident detection capabilities through roadside surveillance devices (e.g. CCTV) and through regional coordination with other traffic management, maintenance and construction management and public safety and emergency management centers as well as weather service entities and event promoters. Information from these diverse sources are collected and correlated by this market package to detect and verify incidents and implement an appropriate response.

This market package also supports traffic operations personnel in developing an appropriate response in coordination with public safety and emergency management, maintenance and construction management, and other incident response personnel to confirmed traffic incidents. Incident response also includes presentation of information to affected travelers using the Traffic Information Dissemination market package and dissemination of traffic incident information to travelers through the Broadcast Traveler Information or Interactive Traveler Information market packages. The roadside equipment used to detect and verify incidents also allows the operator to monitor traffic incident status as the response unfolds. The coordination with public safety and emergency management agencies might be through data sharing and integration of public safety CAD and transportation management data and communication systems or through other communication with emergency field personnel.

10.2.5 Technologies and Strategies

Traffic incident management consists of the following major stages as illustrated in Figure 10-2:

  • Detection
  • Verification
  • Motorist Information
  • Response
  • Site Management
  • Traffic Management
  • Clearance
  • Recovery
chart showing timeline and stages that comprise traffic incident management, from detection to recovery

Figure 10-2: Timeline of Stages in the Traffic Incident Management Process D

A wide variety of techniques and approaches can be applied to each of these stages. These are summarized below with further detail found in Reference 1.

Detection is determining that a traffic incident has occurred. Rapid detection is necessary to minimize the period of time during which roadway capacity is reduced. Methods commonly used to detect incidents include:

  • Cell phone calls from motorists
  • CCTV images viewed by operators
  • Traffic stream probes such as toll tags with software to estimate travel time between readers
  • Electronic detection (video processing, radar, induction loops) with traffic incident detection algorithms
  • Traffic reporting services
  • Service patrols
  • Police patrols
  • Calls from public works crews
  • Helicopter reporters
  • Fleet vehicles
  • Motorist aid telephones / call boxes

Verification is determining the precise location and nature of an incident, as well as the display, recording, and communication of this information to the appropriate agencies. Proper verification is required to reduce the time required to deploy an appropriate response to the scene of an incident. Operations center personnel may verify incidents and communicate with incident responders on scene, or provide details to emergency agency dispatchers. Verification methods include:

  • Field units (e.g. police) at the incident site
  • Closed circuit TV images
  • Communication with helicopters operated by police, media or information service providers
  • Combining or fusing information from multiple cellular calls
  • Airborne platforms or satellites

Motorist information is the activation of a variety of communications media to relay traffic incident conditions to travelers. Dissemination of motorist information is one of the primary services provided by many TMCs, as discussed in Chapters 13 and 14 herein. Techniques include:

  • Commercial radio and television
  • Changeable message signs (CMS)
  • Highway advisory radio (HAR)
  • Telephone information systems
  • In-vehicle or personal data assistant information
  • Internet/on-line services
  • Information service providers (ISP)

Response is the activation, coordination, and management of the appropriate personnel, equipment, and communication links and motorist information media as soon as it is reasonably certain that a traffic incident has occurred. Timely and effective response reduces the incident's duration, and therefore, the time of roadway operation at reduced capacity. Techniques include:

  • Interagency response planning and mutual-aid agreements
  • Intra- and inter-agency communications. This includes voice radio interoperability, data and video links between public safety communication centers (CAD systems), TMCs and highway operations centers. (See Reference 10 and
  • Personnel and logistics support
  • Equipment storage sites
  • Advanced response vehicles that include a mobile communications platform, GPS and other features to facilitate efficient response

Site management consists of:

  • Accurately assessing incidents
  • Properly establishing priorities
  • Notifying and coordinating with appropriate agencies and organizations
  • Maintaining clear communications among responders

Effective site management increases safety for crash victims, motorists and responders; coordinates responder activities; and decreases the impacts of incidents on the transportation system. Techniques include:

  • Institution of an Incident Command System (ICS)
  • Use of Unified Command Structure of ICS for major incidents (Refer to Chapter 12 herein for more information regarding ICS).
  • Identification and implementation of equipment requirements
  • Coordination of multi-agency response
  • Proper placement and staging of response vehicles at traffic incident scenes

Traffic management is the application of traffic control measures at the incident site and on facilities affected by the traffic incident. Effective traffic management minimizes traffic disruption while maintaining a safe workplace for responders and reducing the likelihood of secondary crashes. Techniques include:

  • Preparation
    • Alternate route planning
    • Availability of cones, flares, warning signs, arrow boards, portable CMS and other traffic control resources
    • Availability of traffic control devices such as CMS, HAR, ramp meters, traffic signals
  • Flow management at scene
    • Establish point traffic control at scene
    • Manage roadway space
  • Queue management to actively monitor the end of queue and warn approaching motorists.
  • Flow management on alternate routes
    • Establish and operate alternate routes
    • Actively manage traffic control devices
  • Reduce long-term traffic incident duration

Clearance is the removal of vehicles, wreckage, debris, spilled material and other items from the roadway and the immediate area to restore roadway capacity. Improving traffic incident clearance procedures can:

  • Restore the roadway to its pre-incident capacity quickly and safely
  • Minimize motorist delay
  • Make effective use of all resources
  • Enhance the safety of responders and travelers
  • Protect the roadway and private property from unnecessary damage during the removal process
  • Improve the public image of the response agencies

Refer to Reference 5 for a synthesis of traffic incident clearance policies and strategies.

Techniques include:

  • On-site clearance planning
  • Tow trucks and heavy-duty wreckers with sufficient up-righting, lifting and recovery capability
  • Service patrols to remove minor incidents
  • Police patrols with push bumpers, jumper cables, water and other supplies to expedite clearance
  • Innovative recovery vehicles, debris recovery systems
  • Effective tow and wrecker service contracts, policies or procedures.
  • Efficient accident investigation procedures and technology including photogrammetry and total station surveying systems
  • Streamlined spill cleanup procedures
  • Accident investigation sites
  • Quick clearance policies
  • Policies for cleanup of minor engine fluid spills
  • Inventory of resources, their locations, and what organizations are responsible for each and contacts for each organization.

Recovery consists of restoring traffic flow at the site of the traffic incident; preventing more traffic from flowing into the area and getting trapped in the upstream queue; and preventing congestion from spilling across the roadway network. Thus it encompasses the activities of site management, traffic management and clearance. First responders normally are focused on the immediate vicinity of the traffic incident and likely do not have the resources or information to handle the "big picture." (The end of the queue can range from 1000 feet to 20 miles back from the site.) Resources including traffic operations centers and their operating staff can facilitate recovery by managing the network-wide effects of traffic incidents and thus hastening recovery.

10.2.6 Emerging Trends

The "Freeway Management State-of-the-Practice White Paper" (Reference 9) identifies the following areas as the "state-of-the-art" (Note: Defined in the reference as "innovative and effective practices and the application of leading edge technologies that are ready for deployment in terms of operating accurately and efficiently, but are not fully accepted and deployed by practitioners"):

  • Traffic incident management systems are focusing more on coordination among multiple agencies than ever before. State of the art systems incorporate data sharing techniques between transportation and public safety agencies. An emerging capability is to integrate CAD information into a freeway management system. CAD-TMC integration is being developed and field-tested and is expected to be deployed extensively in the near future.
  • Automation of key traffic incident management activities to reduce labor-intensive operations such as CCTV monitoring being performed by TMC operators. Algorithms using probe travel time measurements appear to provide promise in automating traffic incident detection functions, with more research required in this area.
  • Integration of public safety Computer Aided Dispatch (CAD) and TMC data systems. Incidents detected via cell phone calls will then be known to the TMC, which can then take appropriate actions. Also, transportation and safety agencies will be able to more quickly identify the problem and coordinate their actions.

Reference 11 identifies seven top issues as a roadmap to the future to improve traffic incident management program planning, field operations, and inter-agency communications as follows:

  • Professionalize incident management (Institutional)
  • National program models and guidelines (Institutional)
  • Creation of standards and guidelines for performance data (Institutional)
  • Recognize regional focus in developing, operating, funding TIM technologies (Technical)
  • Develop regional / cross-agency systems architectures (based on standards) (Technical)
  • Establish a clearinghouse for incident management data (Operational)
  • Integrate TIM needs into highway planning and design (Institutional)

10.3 Implementation and Operational Considerations

While the specific form and nature of the above techniques and strategies vary from region to region, elements of successful programs have much in common. These implementation and operational elements fall into three major categories – people, practices, and infrastructure as summarized below.


  • Traffic Incident Management Administrative Teams represent public and private stakeholders and meet regularly to discuss program, policy and procedural issues. A TIM Administrative Team is the working body (mid-level managers) that coordinates activities of the stakeholders and makes program and budget recommendations to the multi-agency TIM Program Steering Committee (upper level and CEO).
  • Incident Response Teams (IRT) are interdisciplinary teams specially trained to handle a range of roadway emergencies.
  • Multi-agency training proves fundamental in maintaining and improving traffic incident management, safety and program quality.
  • Field guides (paper or electronic) supplement training and are tailored to the nature, scope and resources of each region's program.


  • Service patrols are roving vehicles that patrol to provide motorist assistance and handle minor incidents. They can effectively reduce detection time and the duration of the incident. Outstanding examples are found in Chicago, Minneapolis, the San Francisco / Oakland Bay area and Northern Virginia / Washington, D.C.
  • Post-incident debriefings can identify areas for improvement and confirm the value of effective practices.
  • Inter-agency agreements
  • Policies and relationships with private towing companies
  • Wrecker service contracting and updating towing minimum requirements
  • Contracts for special equipment such as heavy-duty cranes and rotators
  • Policies regarding the removal of truck cargo following an incident
  • Enhanced accident investigations by enforcement agencies using technology to support more rapid and efficient completion
  • Ordinances relating to traffic incident removal
  • Documentation and evaluation can quantify and articulate the program's value relative to cost. This can prove important in convincing policy makers to provide funding and support for the program. Commonly used statistics to evaluate traffic incident management programs include:
    • Number of service patrol assists
    • Average elapsed time from traffic incident occurrence to detection
    • Average IRT response time
    • Average elapsed time to restoration of capacity


Intelligent Transportation Systems (ITS) – the application of advanced sensor, computer, electronics and communication technologies – complement traffic incident management programs to maximize the efficiency and safety of the transportation infrastructure. ITS can assist in many of the stages of traffic incident management, particularly:

  • Detection via electronic sensors and traffic incident detection software
  • Verification via closed circuit television
  • Motorist information via dynamic message signs, in-vehicle devices, kiosks, Internet
  • Response via the coordination afforded by a Traffic Operations Center (TOC), as well as computer aided dispatch (CAD), and center-to-center communications.

10.4 Examples

Examples are provided in Reference 1, with two summarized here.

10.4.1 Chicago, Illinois Service Patrol

Chicago's service patrol program, which was kicked off by the Illinois Department of Transportation (IDOT) in 1960, is one of the country's oldest and most successful. The Emergency Traffic Patrol (ETP) initially consisted of several pickup trucks operating during peak periods only. Today, the program, known as Minuteman, has a much broader scope than other service patrols. Whereas most programs focus on removing minor incidents, Minuteman is part of the entire incident response program for IDOT and can clear large truck and cargo spill incidents as well as minor incidents. The program operates around the clock and includes 35 emergency patrol vehicles (the size of a medium-duty tow truck), 11 light utility 4 x 4's, a sand truck, a step van, a tractor / retriever, two 50-ton and two 60-ton heavy-duty recovery units. Every vehicle in the fleet is equipped with heavy-duty push bumpers. One of the country's larger programs, ETP's staff includes 76 positions:

  • Fifty-five patrol drivers, who are known as Minutemen
  • Three shift supervisors
  • Eight foremen
  • Two mechanics
  • A storekeeper
  • An equipment technician
  • Five building and office staff, and
  • A patrol manager

IDOT Minutemen receive comprehensive initial training and frequent ongoing and re-certification training. The patrol operation encompasses 12 beats, which are organized along overlapping shifts and routes to provide extra coverage on high-incident sections. All beats are patrolled 24 hours a day, 365 days a year.

In all, the ETP logs an estimated 1.8 million miles per year. Minutemen typically spend up to 15 to 20 minutes with a motorist at a disabled vehicle. If the disability cannot be corrected, the Minutemen call a motor club or the State Police to order a tow. The Minutemen can transport motorists off the freeway if they so request. Although disabled vehicles are relocated to a shoulder, accident investigation site, or nearby exit, the service patrol does not tow vehicles beyond these points.

A 1990 program evaluation found a benefit-cost ratio of 17:1. Public support for the program is high, as demonstrated by the 900 thank you letters received each year.

10.4.2 Washington State Department of Transportation (WSDOT) Documentation and Evaluation

The Washington State Department of Transportation's (WSDOT) incident response program developed a relational database to organize and store incident records. WSDOT Incident Response Team (IRT) members collect a wide and comprehensive range of data for each incident to which they respond. Data are entered into a portable computer in the field. The data comprising the WSDOT incident response database are identified in Table 10-2.

In 1997, using this database, an independent team of faculty and research engineers evaluated WSDOT's incident management program. The evaluation was based on three measures of effectiveness: (1) congestion mitigation, (2) benefit to cost ratio, and (3) positive public perception. The evaluation revealed substantial benefits associated with the program, including a 12 percent drop in the time required to clear an incident over a two-year period. Another positive finding was a benefit-to-cost estimate in the range of 4:1 to 13:1. The evaluation also pointed out areas for improvement.

Table 10-2: WSDOT Incident Response Database Elements
Category Information
Location (City and County)
  • Nearest city
  • County in which the incident occurred, by code
General Information
  • Name of person preparing the report
  • Date of the report
  • Date of the incident
  • Time of the incident
  • Time the IRT received the call to respond to the incident
  • Time the first IRT member arrived at the scene
  • Date and time incident ended
  • Time last IRT member left the scene
  • Repair notes
WSDOT Personnel
  • Number of WSDOT employees involved
  • Number of hours each was at the incident site
Location (WSDOT Region and Maintenance Area)
  • WSDOT Region and Maintenance Area in which the incident occurred
  • Regional Maintenance Area number
Highway / Route Information
  • State route number and nearest milepost number
  • Description of the intersection if state route and milepost number not available
  • Travel direction of affected lanes
  • Lanes closed (i.e. ramp, single lane, multiple lanes, all lanes in one direction, or all lanes in both directions)
  • Roadway surface
  • Reason for road closure (i.e., single-vehicle accidents, multiple-vehicle accidents, fatal accidents, hazardous and non-hazardous material spills)
Travel Conditions
  • Weather conditions (i.e., rain, snow, fog, wind, calm and clear)
  • Road conditions (i.e., dry, wet, ice-covered, snow-covered)
  • Light conditions (i.e., day, dawn, dusk or night – night with street lights on, night with street lights off, or night with no street lights at all)
Agency Participation
  • Agencies present at the incident site (WSDOT, Washington State Patrol, Department of Ecology, County Emergency Services, Fire Department, County Police, City Police, or other)
  • WSDOT equipment used
  • Incident Response Team equipment used
  • Non-WSDOT equipment used
Materials and Maintenance
  • IRT vehicle materials used
  • Follow-up maintenance
  • Delayed cleanup until off-peak time
  • Conditions at the incident scene (i.e., presence of hazardous materials, non-hazardous materials, fuel spillage, fire, flammable liquid, corrosive material, explosive material, radioactive material, or toxic materials)
  • Agency responsible for cleanup
Traffic Control
  • Lane where the incident originated
  • Detour route, if applicable
  • Occurrence of incident in construction zone
  • When lanes opened
  • Method of Washington State Patrol investigation (i.e., tape, total station equipment)
  • WSP accident and case number (if applicable)
  • Lead investigating agency (WSP, county, city)
  • Number of vehicles involved in the incident
  • Number of injuries
  • Number of fatalities
Number of Vehicles
  • Number of vehicles by type (e.g., one bus, two passenger cars, and a taxi)
Causing Party's Vehicle Type
  • Type of vehicle the causing party was driving
Driver and Vehicle Identification
  • Driver's last name, first name and middle initial
  • Driver's license number
  • State or province in which the licenses were issued
  • Vehicle license number of the party at fault
  • Vehicle year, make, model, and vehicle identification number
  • State or province that issued the vehicle license of the party at fault
  • Insurance of the party at fault
  • Insurance company
  • Description of cargo that was cleared from incident, how it was disposed of, of whether it was stored, etc.
  • Other information / comments

10.5 References

1. Federal Highway Administration, Traffic Incident Management Handbook, November 2000,

2. Federal Highway Administration, Incident Management Successful Practices: A Cross-Cutting Study, April 2000. Reports traffic incident management program benefits and lessons learned in addition to summarizing keys to effective traffic incident management training, leadership, and interagency coordination.

3. Federal Highway Administration, Regional Traffic Incident Management Program: An Implementation Guide, May 2001. Documents a framework for establishing and sustaining a traffic incident management program.

4. Transportation Research Board, Special Report 260: Strategic Highway Research: Saving Lives, Reducing Congestion, and Improving Quality of Life, November 2001. Presents the goals and objectives of a research program, funded by and commencing with the next federal-aid highway program authorization, aimed at preventing and reducing the impact of nonrecurring incidents.

5. Transportation Research Board, NCHRP Synthesis Topic 33-05, Safe and Quick Clearance of Traffic Incidents, 2003. This TRB study assesses the state-of-the-practice and identifies successful policies and strategies to effect quick clearance of traffic incidents.

6. Federal Highway Administration, Managing Travel for Planned Special Events, 2003

7. U.S. Department of Transportation, Version 4.0 of the National ITS Architecture,

8. Federal Highway Administration, Traffic Incident Management (TIM) Self-Assessment Guide

9. Federal Highway Administration, "Freeway Management and Operations: State-of-the-Practice White Paper", January, 2003

10. National Task Force on Interoperability, Why Can't We Talk? Working Together to Bridge the Communications Gap to Save Lives, A Guide for Public Officials, January 2003.

11. National Conference on Traffic Incident Management, March 11–13, 2002, Irvine, CA.