Emergency Transportation Operations

Best Practices in Traffic Incident Management
September 2010

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TIM activities are typically categorized into five overlapping functional areas:

  • Detection and verification.
  • Traveler information.
  • Response.
  • Scene management and traffic control.
  • Quick clearance and recovery.

Actions taken in any one of the five functional areas may be concurrent with actions taken in a different functional area. For example, public information officers may be continuously giving out traveler information while scene management and clearance actions are being taken at the incident scene.

Responders may encounter various challenges in the conduct of these TIM functions. Over time, various tools and strategies have been developed and implemented in an effort to overcome the most common impediments and improve overall TIM efforts. The remainder of this chapter describes common challenges and potential strategies for improvement for each of the five TIM functional areas. Whenever possible, the reader is directed to example applications, reported either in the published and electronic information sources or by participating TIM practitioners, to support additional information gathering regarding a particular tool or strategy of interest.

Detection and Verification

Detection and verification are the first steps in the TIM process. Detection is the determination that an incident of some type has occurred. Incidents may be detected in person by motorists or response personnel or automatically using electronic loop detectors and associated incident detection algorithms. Verification is the determination of the precise location and nature of the incident. Accurate and detailed information about the incident can help to ensure that the most appropriate personnel and resources are dispatched to the scene. Verification can be accomplished in the field utilizing on-site response personnel or remotely using CCTV.

Effective incident detection and verification can improve access to the scene for incident responders, support appropriate personnel and equipment dispatch to the scene, improve responder safety by alerting them to potentially dangerous conditions at the scene (i.e., fire or hazardous materials), reduce secondary incidents, and save lives by ensuring that vehicle crashes are detected on low-traffic roadways.

Common challenges to effective incident detection and verification include the following:

  • Inconsistent notification of incident responders. Typically, public safety agencies, including law enforcement, fire and rescue, and EMS agencies, are the first to be notified of an incident through 9-1-1 dispatch. Notification of support incident responders, particularly transportation agencies, can be less consistent. If transportation agencies do not support 24-h operations or promote an active role in TIM, public safety personnel may overlook their notification. In addition, if no formal guidelines are in place for notifying support responders, or if recently instituted guidelines are not being followed, support personnel notification may vary depending on the particular public safety personnel managing the incident.

  • Inaccurate incident reports. Motorists who carry cellular telephones are commonly the first to detect an incident and provide notification. While the speed with which the incident is reported is beneficial, motorists may not provide accurate location information and may exaggerate incident severity. Motorists may use landmarks to describe the incident location rather than roadway identifiers and may confuse directional information. As a result, unnecessary, inadequate, or insufficient response resources may be dispatched to the incident scene.

  • Dispatcher overload. Often, especially after the occurrence of a major incident, dispatchers receive multiple calls from motorists reporting the incident. These multiple calls can overload dispatchers and limit their attention to other emergencies.

  • Slow detection. In urban areas, higher traffic volumes and a prevalence of cellular-telephone users in the traffic stream generally result in quick and reliable incident detection times. In nonurban or remote areas, where passing vehicles are less frequent, incidents may go undetected for some time. Early detection helps to ensure prompt medical attention and a reduction in secondary incidents.

Table 1 identifies the various tools and strategies that have proven effective in overcoming these challenges and identifies select locations where these tools and strategies are in use. Note that select detection and verification strategies may be most appropriate for distinct implementation in rural or urban environments. For example, motorist aid call boxes and automated collision notification systems (ACNSs) may result in greater benefit when implemented in rural areas, while CCTV cameras are best suited to urban environments. Additional tools and strategies that were more variable in their reported effectiveness—such as electronic loop detectors and probe vehicles to improve slow incident detection or incident notification protocol to lend consistency to incident notification—are included in appendix B.

Table 1. Detection and verification challenges, strategies, and select implementation locations.
DETECTION AND VERIFICATION STRATEGIES Inconsistent Notification Inaccurate Incident Reports Dispatcher Overload Slow Detection EXAMPLE APPLICATIONS
Field Verification by On-Site Responders No Value No Value No Value NY (Hudson Valley Region)
Closed-Circuit Television Cameras No Value No Value No Value 76+ U.S. Metropolitan Areas, MD
Frequent/Enhanced Roadway Reference Markers No Value No Value No Value FL, NJ/PA (Delaware Valley Region), OH, TN
Enhanced 9-1-1/Automated Positioning Systems No Value No Value TX (San Antonio)
Motorist Aid Call Boxes No Value No Value No Value 27+ U.S. Metropolitan Areas, GA
Automated Collision Notification Systems No Value No Value No Value 16+ U.S. Metropolitan Areas, NY (Erie Co.)

Additional descriptive information regarding the various tools and strategies and select locations where these tools and strategies are in use is provided below.

  • Field verification by on-site responders. A common means of incident verification is through the initial dispatch of law enforcement personnel to the incident scene. Once on-scene, the officer assesses the incident, determines response needs, and requests appropriate response through dispatch. This method is particularly effective where traffic congestion does not unduly restrict travel time to the detected incident. Service patrols, described later in this document, can provide similar incident verification capabilities. Under congested conditions, roving service patrols may be quicker to arrive at an incident scene due to their closer proximity. The effectiveness of field verification by on-site responders under either scenario can be improved with a high degree of interagency cooperation and coordination.

    In the Hudson Valley region in New York, Highway Emergency Local Patrol (HELP) service patrol vehicles are equipped with a live video stream back to the traffic management center (TMC) housing the New York State Department of Transportation and State Patrol. Onboard dash cameras relay real-time incident information to dispatchers ensuring the proper and expedited dispatch of equipment. The use of streaming video was found to be extremely helpful for remote transportation and law enforcement personnel in determining the incident characteristics and subsequent response needs. (6)

  • Closed-circuit television cameras. CCTV cameras provide limited-access video images for traffic-monitoring purposes. Improvements in picture quality, pan and zoom capabilities, and video data transmission rates have made CCTV a very useful incident verification tool. Whereas electronic loop detectors (described in appendix B) provide detection capabilities but no verification, CCTV cameras provide verification capabilities but only limited incident detection functions. Experience has shown that manual monitoring of CCTV images leads to a “blank stare”; even if an incident is visible on the screen, the viewer may not register it. The two technologies may best be used in combination. Evaluating the combined use of electronic loop detectors and CCTV cameras, a study conducted in Maryland reported a benefit-to-cost ratio of 5.6:1, including a 5 percent (2 million vehicle-hours per year) decrease in delay associated with nonrecurrent congestion. (7)

    The effectiveness of CCTV cameras is dependent upon the extent and adequacy of camera coverage. In 2007, the ITS Deployment Survey estimated that approximately 36 percent of all freeway miles across 76 U.S. metropolitan areas were equipped with CCTV cameras. (2)

  • Frequent/enhanced roadway reference markers. Installing more frequent roadway reference markers can help to ensure that motorists accurately report incident location. Additional directional and route information can also be included on the markers.

    A number of urban areas across the Nation rely upon frequent/enhanced roadway reference markers to accurately locate incidents:

    • Roadway reference markers, provided every 0.2 mi along urban freeways in Ohio, help motorists quickly and accurately identify the location of an incident. Dispatchers are trained to direct motorists to look for and report these roadway identifiers. (8)
    • Similarly spaced roadway reference markers along urban freeways in Chattanooga, Knoxville, Memphis, and Nashville, TN, have proven additionally beneficial to HELP service patrol operators, law enforcement personnel, fire and rescue personnel, and other TIM personnel in accurately communicating incident location. (9)
    • In the Delaware Valley region in New Jersey and Pennsylvania, TIM personnel rely on ramp reference markers at complex intersections for accurate identification of incident locations. A corresponding map is provided to dispatchers for reference.

    Supporting more widespread implementation, a recent study conducted by the statewide TIM team in Florida concluded that frequent/enhanced roadway reference markers were beneficial to TIM operations. (10)

  • Enhanced 9-1-1/automated positioning systems. Enhanced 9-1-1 systems—that automatically associate a physical address or location with the caller’s telephone number, display the caller’s location information to the dispatcher, and route the call to the most appropriate PSAP—can improve both the accuracy of incident reports and help to alleviate dispatcher overload. For incoming calls made from cellular telephones, a variety of automated positioning techniques are used. Cellular geolocation relies on the time difference of cellular signal arrival and the angle of arrival to determine incident location. The cellular tower location or the latitude/longitude of the caller may be displayed. GPS utilizes a chip installed in each cellular telephone to locate the originating call.

    The next generation of 9-1-1 (NG 9-1-1) systems, whose development is currently being guided by a National Next Generation 9-1-1 Initiative, will be designed to better respond to text, data, images, and video, which are increasingly common in wireless personal communications. (11,12) Moving forward with implementation, Bexar, Comal, and Guadalupe Counties near San Antonio, TX, are implementing an NG 9-1-1 system to manage text messaging, voice-over-Internet protocol, and cellular telephone camera images and video. The upgrade will be accomplished over a 5-yr period at a cost of $24 million, provided largely through telephone customer fees of $0.22 per month for landline telephone accounts and $0.50 per month for cellular telephone accounts. (13)

  • Motorist aid call boxes. In 2007, the Intelligent Transportation Systems (ITS) Deployment Survey estimated that approximately 10 percent of all freeway miles in the United States across 27 metropolitan areas were equipped with motorist aid call boxes. (2) Motorist aid call boxes are permanently mounted roadside communications devices that allow motorists to request assistance or report an incident. Typically, call boxes are installed at bridge or tunnel locations where incident impacts are significant or in remote areas where alternative communications services (e.g., cellular service or pay phones) are limited. Contemporary motorist aid call box systems support two-way voice communication that allows the exchange of additional information about the incident. Safety concerns have been expressed regarding the need for motorists to exit their vehicles and walk to use the call box, exposing them to passing traffic.

    Assuming a reduction of one injury per year and one fatality every 5 yr, motorist aid call boxes installed along 39 mi of rural I-85 in Georgia were estimated to yield a benefit-to-cost ratio of 2.76:1, with an associated cost savings of $329,820. (3) In a public opinion survey conducted 1 yr later, 97 percent of respondents felt that call boxes on rural interstates in Georgia were a good idea even though 64 percent of them owned cellular telephones. Also, 78 percent of respondents indicated a willingness to pay a fee as part of their annual vehicle registration to fund the installation and maintenance of additional call boxes. (4)

  • Automated collision notification systems. More than a dozen commercial ACNSs are currently on the market, available either as factory-installed options on high-end luxury vehicles or as after-market products. ACNSs serve to improve detection of incidents in remote areas through either the automatic or motorist-initiated activation of an alarm and verification of a vehicle’s location through the automatic transmission of location data. The most popular position location technologies include global positioning system (GPS) and cellular geolocation techniques that rely on the time difference of cellular signal arrival and the angle of arrival.

    ACNSs typically utilize wireless communication and a third-party response center to notify the closest public safety answering point (PSAP) for emergency response. In anticipation of ACNS proliferation and subsequent increases in call volumes, emerging strategies are currently under investigation that would allow for direct communications between ACNSs and PSAPs, eliminating the need for a third-party response center. Proposed strategies may utilize existing PSAP infrastructure, such as text telephone (TTY) systems required at all PSAPs under Federal law, or require various infrastructure upgrades depending on the nature of communications. In 2007, the ITS Deployment Survey reported that law enforcement agencies in 16 U.S. metropolitan areas and fire and rescue agencies in 6 U.S. metropolitan areas had access to data from ACNSs to speed incident detection. (2)

    In Erie County, NY, a field operational test found that ACNS reduced incident detection time from an average of 3 min to less than 1 min. Maximum detection times for vehicles equipped with ACNS was 2 min, while the maximum detection times for unequipped vehicles was as high as 46 min. (5)

Traveler Information

Traveler information is the communication of incident-related information to motorists who are at the scene of the incident, approaching the scene of the incident, or not yet departed from work, home, or other location. This information serves to reduce traffic demand and improve responder safety at the incident scene, reduce the potential for secondary incidents for motorists approaching the scene, and allow motorists to alter their travel plans on the basis of current traffic conditions. To ensure motorist cooperation, traveler information tools or strategies should:

  • Advise motorists of the nature and extent of the problem so that they may make intelligent choices about alternative routes or delayed trip departures.
  • Provide information on possible courses of action such as alternative routes.
  • When motorists are required to take certain actions (e.g., change lanes, reduce speed, or divert), describe those actions clearly.

Traveler information should be provided as early in the TIM process as possible and should continue until the incident has been cleared and the traffic backup has dissipated. Common traveler information challenges relate to the following:

  • Inaccurate traveler information. The lack of a sophisticated surveillance system is often blamed for poor traveler information. Miscommunication and a lack of communication among various responding agency personnel, dispatchers, and the media are more often the reasons. The accuracy or detail of information that is passed from responding personnel to the dispatcher is not always maintained when the information is passed to a third party. In addition, dispatchers and the media must try to assimilate sometimes conflicting information from a variety of sources.

  • Inconsistent dynamic message sign use. Two different schools of thought exist regarding the use of DMSs during non-incident times. The first suggests that only emergency or incident-related messages should be displayed so that when it is necessary for motorists to be alert or take action, they will pay attention to the sign. Repetitious, nonemergency messages are thought to dull motorists’ sensitivity to the message. The second school of thought views repetitious observance of the sign as a benefit. Non-incident-related information, such as carpool information or safety reminders (e.g., “Buckle Up”), accustoms motorists to observing the signs for traffic-related information. During an incident, it is likely that they will turn to DMSs for information out of habit. In addition, leaving the sign blank may lead drivers to believe that it is not working.

Table 2 identifies the various tools and strategies that have proven effective in overcoming each of these challenges and identifies select locations where these tools and strategies are in use. Note that additional tools and strategies that were more variable in their reported effectiveness—including incident update protocols and highway advisory radio (HAR)—are included in appendix B.

Table 2. Traveler information challenges, strategies, and select implementation locations.
5-1-1 Systems No Value 33+ States
Traveler Information Websites No Value 39+ States
Media Partnerships No Value 53+ U.S. Metropolitan Areas
Dynamic Message Signs No Value 81+ U.S. Metropolitan Areas, CA (Stockton)
Standardized DMS Message Sets/Use Protocol No Value 73+ U.S. Metropolitan Areas, TX (Austin, San Antonio)

Additional descriptive information regarding the various tools and strategies and select locations where these tools and strategies are in use is provided below.

  • 5-1-1 systems. Similar to the national telephone numbers for information (4-1-1) and emergencies (9-1-1), 5-1-1 was recently established as the national telephone number for traffic and travel information. Travelers can dial 5-1-1 to access current information for specific routes and roadways, including traffic incidents, roadway blockages, lane closures, weather events, and, in some instances, transit and tourism information. State-level systems vary widely in functionality and may be managed by State departments of transportation, local transportation agencies, or local transit agencies. Some States have incorporated companion web services (described below) that provide more extensive traffic and travel information. The effectiveness of the 5-1-1 system is dependent upon the maturity of the available system and the nature and extent of concurrent marketing to inform the public of this traveler information resource.

    To date, 5-1-1 services are available in 33 States. Since its inception in 1999, more than 112 million calls to 5-1-1 have been registered nationwide. (14)

  • Traveler information websites. The Internet has allowed transportation agencies to widely disseminate traveler information such as real-time traffic congestion, incidents, updates on construction activities, and other transportation-related information to the public. Traveler information websites can also be combined with in-field technologies such as DMS (described below) and HAR (described in appendix B) as part of a broader advanced traveler information system (ATIS). The information is available 24 h a day at a relatively low cost to the provider, and it can be accessed by users from home, from work, or en route if Internet access is available. The effectiveness of traveler information websites is dependent upon the nature and extent of, and level of effort expended to maintain, the traveler information provided on the website.

    In 2007, the ITS Deployment Survey reported that at least 39 States utilize websites to provide traveler information. (2) Approximately one-third of these websites are operated in conjunction with 5-1-1 telephone services described above.

  • Media partnerships. Most traveler information is broadcast over commercial AM and FM radio or television. As an indication of the importance of providing traffic-related information, private traffic-reporting firms that collect, package, and “sell” traffic information to the broadcast media have developed in many urban areas. Cooperative media partnerships help to ensure that public-sector agencies are fully utilizing resource opportunities that exist. Effective media relationships require an understanding of media perspectives, needs, and limitations, as well as a media education effort to stress the importance of accurate and timely information. Multidisciplinary training may provide convenient forums for improving media relations.

    In 2004, the ITS Deployment Survey reported 59, 54, and 15 metropolitan areas in the United States distributing TIM information, providing CCTV camera images, and providing a direct video feed of traffic conditions to the media, respectively. By 2006, the number of U.S. metropolitan areas providing a direct video feed of traffic conditions to the media increased to 53. (2)

  • Dynamic message signs. DMSs—also known as changeable or variable message signs—are useful for providing dynamic information regarding unusual conditions, guidance information regarding diversion, and advance warning of conditions ahead. DMSs can be combined with HAR, websites, and other technologies as part of a broader ATIS. To ensure maximum effectiveness when communicating with the motoring public, the information should be accurate and timely, and the signs should be located carefully to support appropriate diversionary action. Signs can be permanently installed at fixed locations, or portable and mounted on a truck or trailer. Portable DMSs must be able to be quickly mobilized and deployed to be effective.

    In 2006, the ITS Deployment Survey reported at least 3,398 permanently installed and 1,362 portable DMSs used in 81 metropolitan areas in the United States. (2)

    As a quality assurance measure for DMS use, TIM personnel in Stockton, CA, reported using on-site responders to verify the appropriateness of posted DMS messages and to provide requests for updated messages as the TIM process evolves. These DMS message verification procedures by on-site responders were reported to be very effective in enhancing the accuracy of traveler information.

  • Standardized DMS message sets/use protocol. Standard message sets help to ensure the posting of appropriate DMS messages and reduce the need for TIM personnel to redraft unique messages for each incident. Standard DMS message sets that attempt to reflect every possible incident scenario, however, can become large and cumbersome to use and, hence, lose effectiveness.

    To elicit the proper response from motorists, DMS messages must be short enough to be read and understood by a passing motorist. At typical highway speeds, the message posted on a DMS must be presented to motorists in about 8 s or less. This translates to eight words at 55 mi/h, seven words at 65 mi/h, and six words at 70 mi/h. Motorist comprehension can be improved if messages contain the same elements and presentation order. Recommended message elements include a brief description of the situation, the location of the situation, the effect on travel (i.e., delays, lanes blocked, etc.), and the action that the motorist should take. (15)

    Although no national agreement exists on the use of DMSs during non-incident times (i.e., left blank or used to provide nonemergency messages), regional or State-level consistency in DMS use will improve their effectiveness in eliciting motorist compliance. If a situation arises that requires the usage of a specific DMS for more than one ongoing condition, message priority criteria should be used for displaying messages. For example, as part of a recently developed multi-agency incident response plan for the I-35 corridor between Austin, TX, and San Antonio, TX, a hierarchy of DMS use was defined to reflect the following priority: safety, roadway closures, delay information, emergency messages (including AMBER alerts), test messages, and public service announcements. (16) In 2004, at least 73 major metropolitan areas in the United States reported having policies or procedures in place that govern the display of messages on DMSs. (2)


Incident response is the activation of a “planned” strategy for the safe and rapid deployment of the most appropriate personnel and resources to the incident scene. Information management plays an important role in response; providing the necessary information to the appropriate personnel is critical in achieving optimum response. Accurate information about an incident—such as its location, traffic impacts, vehicle types involved, presence of an injury or a fatality, and other special conditions (e.g., presence of a hazardous material)—is essential in determining the proper response. The level of required response is typically determined by an on-scene responder or by a dispatcher at a communications or traffic management center.

The objectives of improved response are to save lives through more rapid EMS response, ensure that responders reach the scene before the traffic backup becomes lengthy, make more efficient use of personnel and resources through “appropriate” response, and achieve a state of continued readiness for the rapid deployment of the appropriate resources to the incident scene and the area affected by it.

Common response challenges relate to the following:

  • Achieving optimum response. Two common, yet undesirable, situations often result when incident response is initiated: under-response and over-response. Under-response results when too few resources or inappropriate resources are dispatched to the scene (e.g., dispatching a light-duty wrecker to an incident involving an overturned semi-truck). Typically, the inadequacy of the personnel or resources first dispatched is not realized until after they have arrived at the incident scene. When additional personnel or equipment is requested to the scene, the subsequent response usually takes much longer because traffic congestion from the incident reduces accessibility. Under-response more than doubles necessary incident response times. An inappropriate solution to the problem of under-response is to dispatch excess personnel or equipment to the scene. Equipment and personnel that are not needed at the scene can cause a bigger congestion and accessibility problem than the incident itself. In addition, over-response greatly reduces an agency’s efficiency by committing personnel and resources unnecessarily. Agencies should instead strive for optimum response, with the correct equipment and appropriate number of personnel dispatched to the incident scene. Optimum response can be attained through improved incident verification techniques and better awareness among responders of the different information needs and capabilities of each agency.

  • Difficult scene access. Traffic congestion and roadway design are the primary reasons for limited access to the scene for incident responders. Traffic congestion complicates access to the scene for responders. Flashing lights, especially amber-colored flashing lights, seem to have little effect on traffic movement (i.e., few people move to the right when a vehicle with flashing lights approaches from the rear). Historically, wide roadway shoulders have supported emergency access when travel lanes are congested. In many urban areas, however, efforts to ease traffic congestion have resulted in wide shoulders being converted to general-purpose or special-use lanes.

Table 3 identifies the various tools and strategies that have proven effective in overcoming each of these challenges and identifies select locations where these tools and strategies are in use. Note that additional tools and strategies that were more variable in their reported effectiveness—including median crossovers and traffic signal pre-emption—are included in appendix B.

Table 3. Response challenges, strategies, and select implementation locations.
RESPONSE STRATEGIES Achieving Optimum Response Difficult Scene Access EXAMPLE APPLICATIONS
Personnel/Equipment Resource Lists No Value 75+ U.S. Metropolitan Areas
Towing and Recovery Vehicle Identification Guide No Value NJ/PA (Delaware Valley Region), TX (Austin)
Instant Tow Dispatch Procedures No Value WA (Seattle)
Towing and Recovery Zone-Based Contracts No Value TX (Houston)
Enhanced Computer-Aided Dispatch No Value 43+ Agencies in U.S. Metropolitan Areas, CA (Los Angeles), NM (Albuquerque), TN (Sequatchie Co.)
Dual/Optimized Dispatch Procedures No Value NJ
Motorcycle Patrols No Value All or Nearly U.S. Metropolitan Areas
Equipment Staging Areas/Pre-positioned Equipment No Value TN, WI

Additional descriptive information regarding the various tools and strategies and select locations where these tools and strategies are in use is provided below.

  • Personnel/equipment resource lists. Problems with indirect communication and unnecessary calls to request personnel or equipment can be minimized through the use of personnel or equipment resource lists. Significant resource information may have already been compiled by local emergency management agencies that perform emergency response planning for hurricanes, tornadoes, earthquakes, chemical disasters, etc. Information compiled in the resource lists should include geographic or jurisdictional response areas, telephone numbers, fax numbers, pager numbers, procedures for radio contact, alternative contacts, available equipment, available supplies or materials, and anticipated response times. This information should be provided for both daytime and nighttime conditions, particularly for nonemergency, support agencies (e.g., transportation departments) that do not operate 24 h a day. Resource lists should be regularly updated to ensure continued benefit.

    In 2004, the ITS Deployment Survey reported at least 75 major metropolitan areas in the United States using personnel/equipment resource lists. (2)

  • Towing and recovery Vehicle Identification Guide. Available as 8.5-inch by 11-inch laminated cards, the Towing and Recovery Association of America (TRAA) Vehicle Identification Guide can be carried in appropriate response vehicles to ensure that responders who are requesting towing and recovery services provide the necessary information to tow operators prior to dispatch. Key information includes the year, make, and model of the vehicle to be towed or recovered; the vehicle’s classification under the U.S. Department of Transportation’s (USDOT’s) classification scheme (examples of vehicle types in each class are depicted); the type of services required (i.e., impound, accident, recovery, or motorist assist); and other pertinent vehicle information (i.e., tire condition, cargo contents, load status, etc.). Use of this guide helps to prevent inappropriate equipment/personnel dispatch, which in turn reduces overall incident duration resulting from sequential, redundant response.

    In Austin, TX, the Texas Department of Transportation and the Austin Towing Association jointly sponsored provision of the TRAA Vehicle Identification Guide for law enforcement, fire and rescue, and transportation agency response vehicles in the metropolitan area. Similarly, the Delaware Valley Regional Planning Commission (DVRPC) in New Jersey and Pennsylvania sponsored provision of the TRAA Vehicle Identification Guide to all TIM personnel.

  • Instant tow dispatch procedures. To expedite response and removal of blocking disabled vehicles, instant tow dispatch procedures initiate response from towing and recovery personnel and law enforcement at the same time, essentially eliminating the on-site verification process. In urban areas, the need for towing and recovery response may still be verified remotely using CCTV cameras.

    In Washington, instant tow dispatch procedures are credited with saving an average of 15 min of lane-blocking congestion each time it is used, with an associated cost savings for each instant tow deployment of approximately $20,000 to $35,000, depending on the location and traffic conditions. Eliminating the verification process may result in “dry runs” for towing and recovery companies. With a dry run fee of $25 per trip, the Washington State Department of Transportation (WSDOT) reports paying under $100 per month for coverage along all State and interstate highways in the Seattle metropolitan area. (17)

  • Towing and recovery zone-based contracts. The two most common contracting mechanisms for providing towing and recovery services include rotational lists or zone-based licensing. Based on responses from 29 U.S. jurisdictions, 55 and 21 percent utilized rotational lists and zone-based licensing, respectively. (18) The latter approach—under which a single private towing agency is assigned to respond to incidents occurring in a predefined geographic area or zone—offers the greatest potential for enhancing incident response. Under zone-based contracts, geographic coverage areas are generally defined to support reasonable physical driving distances and associated response times. In addition, towing and recovery operators develop a high level of familiarity with traffic and incident characteristics (i.e., congested or high-incident locations) in their area and potential alternate routes for quickly accessing the incident scene. Responders, too, develop a familiarity with the personnel and equipment capabilities of the designated towing and recovery company.

    Irrespective of type, contracts may specify acceptable response times to incident scenes. Input from towing and recovery personnel is important in establishing reasonable response times that can then be strictly enforced. In Houston, TX, qualified contracted towing and recovery companies are responsible for responding within an average of 6 min to incidents on a designated section of State-owned freeways as part of their SafeClear program. During the first year of the program, tow operators responded to more than 60,000 stalls and collisions, response times were under 6 min more than 87 percent of the time, and incidents were cleared in less than 20 min 72 percent of the time. An overall 10 percent reduction in the number of collisions on the freeways was also observed. (19) In 2008, response times by SafeClear program tow operators were under 6 min 89.8 percent of the time, and incidents were cleared in less than 20 min 90.5 percent of the time, frequently without any need for additional responder support. A reduction of approximately 1,440 incidents per year is attributed to the SafeClear program’s expedited response and clearance times, resulting in an economic savings of nearly $49 million per year. (20) The Texas Department of Transportation has similarly worked with various heavy-duty tow operators in Houston, TX, to define an acceptable 50-min response time to incident scenes involving large trucks.

  • Enhanced computer-aided dispatch. Enhanced computer-aided dispatch (E-CAD) systems—more commonly used by law enforcement, fire and rescue, and EMS—utilize automatic vehicle location (AVL) technologies to locate, dispatch, and route emergency vehicles closest to the incident scene to minimize response time. E-CAD systems continuously update all information so that current field conditions can be viewed at any time.

    In 2004, the ITS Deployment Survey reported at least 43 public safety agencies in major metropolitan areas in the United States using E-CAD systems. (2) Examples of E-CAD systems in use across the Nation include the following:

    • On a small scale and utilizing a $25,000 grant to buy four new laptop systems, Sequatchie County, TN, equipped its ambulances with technology that combines digital information from 9-1-1 dispatch centers, utility authorities, and the county property assessor’s office with real-time incident information updated every 2 s. (21)
    • Similarly, Albuquerque Ambulance in New Mexico uses a map-based E-CAD system that allows the dispatcher to provide en-route ambulance drivers with the exact location of an emergency and guidance on appropriate routes. The company’s efficiency has reportedly increased by 10 to 15 percent. (22)
    • On a larger scale, the Loma Linda University Medical Center east of Los Angeles—a regional trauma center for four counties—began developing its Advanced Emergency Geographic Information System (AEGIS) using a $500,000 Department of Defense grant. Air ambulances were already equipped with GPS. Agreements were established to patch streaming data feeds from area police and fire and rescue agencies, patient-capacity information from other area hospitals, and weather data and traffic images from the California Department of Transportation. In its current form, the system effectively supports crucial routing and staff decisions. An outstanding goal is to provide first responders with the capability to upload incident images prior to departing or en route to the scene. (23)
  • Dual/optimized dispatch procedures. In areas where traffic volumes are high, the distance between interchanges or crossovers is unusually long, or the exact location or direction of an incident has not been verified, dual dispatch procedures may be used to ensure the quickest response to an incident. Under this approach, response units are dispatched in both directions—the first unit to locate the incident provides response, and the other units return to their stations. Dual dispatch has proven to be successful in improving response times to incidents; however, the benefits of dual dispatch procedures may not be fully realized if traffic volumes are high along all routes leading to the incident or if travel distances for supplemental responders are lengthy.

    To minimize the crossovers required under dual dispatch procedures, TIM personnel in New Jersey dispatch according to predetermined, mutually agreed-upon “response box” areas for limited access highways based on the agency’s proximity to an incident rather than its jurisdictional boundaries. Dispatchers have copies of these response box area diagrams and use them to dispatch the closest available resources to the scene.

  • Motorcycle patrols. Motorcycle patrols, which can more easily maneuver in congested areas than larger response vehicles, allow trained personnel to reach and assess the incident scene more quickly. Motorcycle patrols can provide limited initial traffic control and scene protection prior to the arrival of additional resources. The effectiveness of motorcycle patrols is dependent upon the actions taken by law enforcement officers once on-scene; motorcycle patrol officers who administer first aid, secure the scene, and actively manage traffic may be perceived as most beneficial.

    Motorcycle patrols are widely used to support TIM operations, predominantly by law enforcement agencies across the Nation.

  • Equipment staging areas/pre-positioned equipment. For major incidents, significant and varied equipment may be required to clear the incident. Certain pieces of equipment that may be slow to mobilize—such as a front-end loader that needs to be loaded onto a flatbed trailer for transport—should be requested early in the TIM process to minimize lost time waiting for its arrival. Conversely, the early and intermittent arrival of equipment may compromise scene access and maneuverability. To enhance operations, a temporary staging area can be created to organize the equipment and designate its use. The staging area should be near the incident scene and easily accessible to responders.

    Equipment and materials can also be pre-positioned and stored long term at key locations near areas that suffer from high incident rates. Pre-positioned TIM equipment, easily accessible by appropriate responding agencies, speeds the deployment of necessary resources to an incident scene. Tennessee and Wisconsin provide examples of pre-positioned equipment to support TIM operations:

    • Beginning in 2002, the Tennessee Department of Transportation deployed “Ready Response Trailers” stocked with traffic control devices at 15 strategic locations in suburban and rural areas. The intent was to assist with TIM operations outside of the normal HELP service patrol areas. (9)
    • The Wisconsin Department of Transportation stages portable roadway barriers near key freeway access ramps to expedite necessary road closures during major incidents or weather events.

    Cooperative agreements may be required to describe the equipment that would be stored and the responsibilities for keeping the facility stocked and paying initial and ongoing facility costs.

Scene Management and Traffic Control

Scene management is the coordination and management of resources and activities at or near the incident scene, including personnel, equipment, and communication links. The scene management and traffic control phase of TIM occurs after responding agencies have arrived at the scene. Injured persons are immediately attended to, the incident scene is protected, and plans are formulated for scene documentation and wreckage or debris clearance. Successful scene management relies heavily on interagency cooperation and traffic control strategies. For minor incidents, scene management is relatively simple, usually involving just a single agency (e.g., a transportation agency) or a single agency and a company (e.g., a police agency and a wrecker company). Scene management becomes much more complicated as the severity of the incident increases. The number of responding agencies and companies and the number and complexity of individual tasks consequently increase.

The objectives of improved scene management and traffic control are to effectively coordinate the activities of multiple agencies, improve interagency and intra-agency communications, maximize the use of personnel and resources, and improve the safety of motorists and responders through traffic control. Because much of scene management deals with personnel coordination, measured benefits of improved site management efforts are seldom available.

Common challenges to effective scene management and traffic control include the following:

  • Confusion over authority/roles. Response personnel at the scene of an incident are often required to make quick decisions that may have serious or even life-threatening implications. Disagreement among response personnel regarding the proper actions to take can lead to additional stress at the incident scene and can have a lasting, damaging effect on long-term interagency relationships. The question of who is “in charge” often arises when disagreement exists. One of the more common disagreements involves when to close a roadway to traffic. The disagreement over this issue stems from differing agency priorities. Transportation personnel traditionally have pressed to keep the roadway open to alleviate traffic congestion and prevent secondary incidents. Police and fire and rescue agencies have traditionally encouraged road closure to protect response personnel from passing traffic and to maintain the integrity of evidence at the scene.

  • Difficult on-scene maneuverability. Accessibility to and maneuverability at the incident scene can be complicated by the incident response or emergency vehicles already at the scene. Traditionally, response vehicles have been parked where convenient without thought to access or roadway blockage. When a response vehicle must be moved, often the driver of the vehicle is not nearby, resulting in unnecessary delays at the scene.

  • Responder safety. Since 2003, more than 59 law enforcement, 12 fire and rescue, and 54 highway maintenance personnel have been killed after being struck by vehicles along the highway, according to the Bureau of Labor Statistics. (24) Data on towing and recovery industry occupational fatalities are not well tracked. However, TRAA anecdotally reports a loss of about 100 towing operators in the line of service annually. (25) The occurrence of responder injury or “near misses” is much higher.

  • Secondary incidents. Secondary incidents caused by unsuspecting approaching motorists may increase both the number and severity of injuries attributable to incidents and compound the impact of congestion and time taken to clear the roads. Minor incidents, if not cleared quickly, can result in more serious, major incidents. A passing vehicle may strike a disabled vehicle on the shoulder, seriously injuring the vehicle occupants or a pedestrian changing a flat tire on the side of the road. Major incidents can also lead to multiple minor incidents. If a traffic queue forms behind a major incident, minor incidents such as fender bender crashes are likely to occur. Each of these minor incidents, in turn, needs attention from response agencies. Incidents can be considered secondary to a primary incident if the time and location of the incident can be correlated with the primary incident, including the queue dissipation times. Accurately quantifying the number of secondary incidents is challenging; a high proportion of secondary incidents is likely minor and may never be formally reported to police agencies. Although no standard measure has been historically defined to identify secondary incidents, most estimates suggest that between 14 to 18 percent of the total incidents are secondary in nature. (26)

  • Excess delay. The 2007 Urban Mobility Report states that motorists in 437 U.S. urban areas incurred $78.2 billion in congestion costs in 2005, with 52 to 58 percent of the total motorist delay attributed to crashes and vehicle breakdowns. (27) Roadway capacity reductions exceed the physical blockage resulting from an incident, exacerbating congestion and delay levels. The temporary obstruction of one and two travel lanes along a three-lane freeway is estimated to reduce the available capacity of the facility by 63 and 77 percent, respectively. (28) Incidents located wholly on the shoulder of a roadway are estimated to reduce the available capacity of the facility by up to 17 percent, depending on the nature of the incident. (29) Current TIM efforts are credited with reducing annual delay by 129.5 million h with an associated cost savings of approximately $2.5 billion. (27) Cost savings attributable to reduced fuel consumption and harmful emissions are included in these estimates.

Table 4 identifies the various tools and strategies that have proven effective in overcoming each of these challenges and identifies select locations where these tools and strategies are in use. Note that additional tools and strategies that were more variable in their reported effectiveness—such as intrusion detection/warning systems, secondary and responder-involved incident tracking, responsive traffic signal control systems, alternative traffic signal timing plans, active lane/ramp controls, and reserved/special-use lane temporary use policies—are included in appendix B.

An additional challenge that is not listed here relates to limited on-scene communications. When agencies from different or multiple jurisdictions need to coordinate response actions on-scene, direct communications may be prevented by incompatible radio systems. Consequently, when responding to a major incident, agencies must cope with other, inefficient means of communications. For example, law enforcement personnel may want to inform transportation personnel of the need to close a lane temporarily to remove the wreckage from the scene. The transportation personnel may be a significant distance upstream of the incident performing traffic control. Incompatible radio systems prevent the request from being made directly. The various tools and strategies that have been developed and implemented in an effort to overcome challenges related to on-scene communications are described later in this document under “Cross-Cutting Challenges and Strategies.”

Table 4. Scene management and traffic control challenges, strategies, and select implementation locations.
SCENE MANAGEMENT AND TRAFFIC CONTROL STRATEGIES Confusion over Authority/Roles Difficult On-Scene Maneuverability Responder Safety Secondary Incidents Excess Delay EXAMPLE APPLICATIONS
Incident Command System No Value No Value No Value No Value 58+ U.S. Metropolitan Areas, WA
Response Vehicle Parking Plans No Value No Value No Value No Value AZ (Phoenix), CO (Lakewood), IA, MI (Farmington), TX (Lancaster)
High-Visibility Safety Apparel/Vehicle Markings No Value No Value No Value No Value CO (Eagle)
On-scene Emergency Lighting Procedures No Value No Value No Value No Value TX (Austin, San Antonio)
Safe, Quick Clearance Laws—Move Over No Value No Value No Value No Value 47 States, including CA, FL, GA, IN, TN
Effective Traffic Control Through
On-Site Traffic Management Teams
No Value No Value No Value CA (Stockton), FL (Southeast), NJ
End-of-Queue Advance Warning Systems No Value No Value No Value No Value CA (Bishop, Los Angeles, Redding, Stockton), NJ (Camden), TN (Chattanooga), UT (Salt Lake City)
Alternate Route Plans No Value No Value No Value No Value 62+ U.S. Metropolitan Areas, CA (Anaheim), FL (Northeast), ME/NH, NJ/PA (Delaware Valley Region), WI

Additional descriptive information regarding the various tools and strategies and select locations where these tools and strategies are in use is provided below.

  • Incident Command System. The Incident Command System (ICS) is a federally adopted, on-scene command and control protocol that lends consistency to TIM actions, clearly defines command, improves interdisciplinary communication, and more fully utilizes resources. The ICS relies upon a unified command concept whereby management responsibility is shared for the incident. All agencies that have a responsibility at an incident cooperatively determine the overall incident objectives, strategies, planning efforts, integrated activities or actions to take place, and maximum use of resources. Transportation personnel, traditionally untrained in ICS principles, can refer to the Simplified Guide to the ICS for Transportation Professionals, accessible at https://ops.fhwa.dot.gov/publications/ics_guide/ics_guide.pdf, to learn more. (30)

    In 2004, the ITS Deployment Survey reported at least 65 agencies in 58 major U.S. metropolitan areas operating under ICS principles; 26 were required to do so by law. (2) For example, in Washington, the following legislation exists related to the ICS:

    §70.136.030 Incident Command Agencies—Designation by Political Subdivisions. The governing body of each applicable political subdivision of this state shall designate a hazardous materials incident command agency within its respective boundaries, and file this designation with the director of community development. In designating the incident command agency, the political subdivision shall consider the training, manpower, expertise, and equipment of various available agencies as well as the Uniform Fire Code and other existing codes and regulations. Along state and interstate highway corridors, the Washington State Patrol shall be the designated incident command agency unless by mutual agreement the role has been assumed by another designated incident command agency. If a political subdivision has not designated an incident command agency within 6 months after July 26, 1987, the Washington State Patrol shall then assume the role of incident command agency by action of the chief until a designation has been made.

    §70.136.035 Incident Command Agencies—Assistance from State Patrol. In political subdivisions where an incident command agency has been designated, the Washington State Patrol shall continue to respond with a supervisor to provide assistance to the incident command agency.

  • Response vehicle parking plans. Response vehicle parking plans serve to preserve maneuverability at the scene, ensure response personnel safety, protect response personnel at the incident scene, and maintain traffic flow past the incident. While it is not possible to develop parking plans to fit all incident scenarios, it is possible to develop guidelines or policies about how and where response vehicles should be parked so that travel lanes can be opened when they are no longer needed by responders. For example, all responding vehicles should be parked on the same side of the roadway on which the incident occurred. With the exception of vehicles parked to secure the incident scene, response vehicles should be parked on the shoulder to keep from blocking any additional lanes of traffic. Fire personnel are usually directed to park their vehicles directly behind or in front of the cars involved in the emergency, to minimize the disruption of traffic and to reduce the exposure of personnel and apparatus to danger. On-scene tow trucks, sand trucks, and other vehicles should be parked where they can be accessed and moved while not blocking lane-opening activities.

    The International Association of Fire Chiefs’ (IAFC’s) Vehicle Safety Resources website, accessible at http://www.iafc.org/displaycommon.cfm?an=1&subarticlenbr=413, includes links to various standard operating procedures in use by fire and rescue agencies across the Nation that detail appropriate on-scene vehicle parking. Select examples are listed below:

    The effectiveness of response vehicle parking plans is more likely dependent upon TIM practitioner adherence to the response vehicle parking plan rather than the design of the underlying plans. Unless response vehicle parking plans are integrated into TIM intra- and interagency training, consistent adherence to the plan among all incident response personnel will be challenged.

  • High-visibility safety apparel/vehicle markings. The visibility and conspicuity of emergency vehicles have been the subject of significant historic investigation. Most recently the U.S. Fire Administration and the International Fire Service Training Association published the Emergency Vehicle Visibility and Conspicuity Study, intended to improve on-scene safety for all incident responders with a focus on passive visibility/conspicuity treatments. (36) In brief, the study identified several opportunities for improving the visibility and conspicuity of emergency vehicles through the proper placement of retroreflective materials to optimize interaction with approaching vehicle headlamps and the use of contour markings, fluorescent and/or high-efficiency retroreflective materials, and distinctive logos or emblems made with retroreflective material.

    High-visibility safety apparel plays an important concurrent role in ensuring scene safety. High-visibility safety apparel is defined as personal protective safety clothing that is intended to provide conspicuity during both daytime and nighttime usage. In November 2008, 23 Code of Federal Regulations (CFR) 634 was enacted to mandate the use of high-visibility clothing meeting American National Standards Institute (ANSI)/International Safety Equipment Association (ISEA) 107 Class 2 or 3 requirements by anyone working in the right-of-way of a Federal-aid highway. In December 2009, Section 6D.03 of the Manual of Uniform Traffic Control Devices for Streets and Highways (MUTCD) introduced related standards for high-visibility safety apparel:

    Standard: All workers, including emergency responders, within the right-of-way who are exposed either to traffic (vehicles using the highway for purposes of travel) or to work vehicles and construction equipment within the TTC zone shall wear high-visibility safety apparel that meets the Performance Class 2 or 3 requirements of the ANSI/ISEA 107–2004 publication entitled “American National Standard for High-Visibility Safety Apparel and Headwear” (see Section 1A.11), or equivalent revisions, and labeled as meeting the ANSI 107-2004 standard performance for Class 2 or 3 risk exposure, except as provided in Paragraph 5. A person designated by the employer to be responsible for worker safety shall make the selection of the appropriate class of garment.

    Option: Emergency and incident responders and law enforcement personnel within the TTC zone may wear high-visibility safety apparel that meets the performance requirements of the ANSI/ISEA 207-2006 publication entitled “American National Standard for High-Visibility Public Safety Vests” (see Section 1A.11), or equivalent revisions, and labeled as ANSI 207-2006, in lieu of ANSI/ISEA 107-2004 apparel. (37)

    Instituting many of the recommended principles for high-visibility vehicles and safety apparel, the Western Eagle County Ambulance District in Eagle, CO, has instituted a new visibility safety program for vehicles and personnel. Based on European models, three of the district’s vehicles feature distinctive reflective yellow and blue chevron stripes across the back, yellow and blue horizontal stripes along each side, and white contour lines outlining the profile of the vehicle. Ambulance doors are additionally equipped with blinking lights. Ambulance personnel wear the same reflective colors on their windbreaker coats and fleece jackets. (38)

  • On-scene emergency lighting procedures. In the initial stages of an incident, the appropriate use of emergency lights is essential for responder and motorist safety. Emergency lights help speed the response of emergency personnel to the incident and serve as a warning to approaching traffic of the presence of stopped or slowed vehicles in the area. However, the prolonged use of emergency lights at the scene of an incident can have detrimental effects. Emergency lights are often distracting and confusing to motorists, especially at night and for major incidents that involve a number of emergency vehicles. Emergency lights also contribute to congestion as motorists slow down to observe the cause of the flashing lights. Consequently, the use of emergency lights should be reduced as soon as sufficient traffic control (i.e., advance warning signs and traffic control devices) has been established at the incident scene. Specific guidelines can be developed that include general emergency-light use procedures (i.e., turn off forward-facing emergency lights once on-scene; avoid using red or white flashing, strobing, or oscillating lights of any kind around merging lanes to avoid masking the directional arrow lights) and a phased approach for reducing emergency-light use concurrent with the deployment of traffic control devices for scene protection.

    Section 6I.05 Use of Emergency-Vehicle Lighting in the MUTCD, 2009 edition, provides the following guidance related to emergency-light use:

    Public safety agencies should examine their policies on the use of emergency-vehicle lighting, especially after a traffic incident scene is secured, with the intent of reducing the use of this lighting as much as possible while not endangering those at the scene. Special consideration should be given to reducing or extinguishing forward facing emergency-vehicle lighting, especially on divided roadways, to reduce distractions to oncoming road users.

    Because the glare from floodlights or vehicle headlights can impair the nighttime vision of approaching road users, any floodlights or vehicle headlights that are not needed for illumination, or to provide notice to other road users of an incident response vehicle being in an unexpected location, should be turned off at night. (37)

    Consistent with this guidance, on-scene emergency lighting procedures were recently developed as part of a multi-agency incident response plan for the I-35 corridor between Austin and San Antonio, TX, to promote the phased use of emergency lighting on-scene (i.e., use emergency lighting in the initial stages of an incident but reduce emergency lighting as soon as sufficient traffic control is in place), the preferred types of lighting, and the appropriate times and circumstances for use (e.g., when en route to a confirmed incident with injuries or incident that is blocking a travel lane). (16) In addition, the IAFC Vehicle Safety Resources website, identified previously and accessible at http://www.iafc.org/displaycommon.cfm?an=1&subarticlenbr=413, includes links to various standard operating procedures in use by fire and rescue agencies across the Nation that detail appropriate emergency-light use.

  • Safe, quick clearance laws—Move Over. Move Over laws require drivers approaching a scene where emergency responders are present to either change lanes when possible and/or reduce speed with the intent of enhancing responder safety. Move Over laws are commonly included as extensions to pre-existing laws directing a driver to slow and pull to the side of the road to allow emergency vehicles with warning devices activated to pass. These laws have been modified to include driver guidance when approaching and passing stationary emergency vehicles along the roadside. Anecdotally, responders have expressed concern over the lack of Move Over law awareness among drivers and the challenges faced by law enforcement personnel tasked with performing incident management duties and concurrently enforcing Move Over laws.

    At the time of this investigation, all but two States—Hawaii and New York—have enacted Move Over laws. Significant national initiatives, led by the Move Over, America partnership and the American Automobile Association (AAA), have contributed to the proliferation of these laws among States. The AAA initiative encourages enactment of Move Over laws that cover tow trucks and other roadside assistance vehicles in addition to law enforcement vehicles, fire trucks, and ambulances.

    Because the effectiveness of Move Over laws relies heavily upon driver cooperation, the Move Over, America partnership and AAA initiated concurrent national public information campaigns comprised of public safety announcements and other publicity efforts in an effort to raise awareness of driver responsibilities under these laws. Select States, such as Florida, have also included State-mandated driver education initiatives and enforcement directives as part of their legislation:

    §316.126. 2 (c) The Department of Highway Safety and Motor Vehicles shall provide an educational awareness campaign informing the motoring public about the Move Over Act. The department shall provide information about the Move Over Act in all newly printed driver’s license educational materials after July 1, 2002.

    More information regarding Move Over laws, including recommendations for model language, can be found in FHWA’s Traffic Incident Management Quick Clearance Laws: A National Review of Best Practices, accessible at https://ops.fhwa.dot.gov/publications/fhwahop09005/index.htm. (39) In addition, a recent FHWA educational outreach initiative aimed at encouraging the adoption and effective implementation of safe, quick clearance laws, including Move Over laws, is described in Educational Outreach for Safe, Quick Clearance (SQC) Laws and Policies, accessible at https://ops.fhwa.dot.gov/publications/fhwahop10012/tim_sqc.pdf. (40)

  • Effective traffic control through on-site traffic management teams. The rapid deployment of traffic control devices at the scene of an incident not only improves access to the scene for responders but also provides a safe on-scene environment for responders performing TIM duties and minimizes the potential for secondary incidents involving approaching motorists.

    A number of urban areas across the Nation rely upon on-site traffic management teams to ensure the rapid and appropriate deployment of traffic control devices at an incident scene:

    • To ensure adequate scene protection for incident responders, TIM personnel in Stockton, CA, reported using on-site traffic management teams to quickly and effectively establish proper traffic control.
    • Similarly, in New Jersey, an Incident Management Response Team (IMRT) responds to major highway incidents or planned events and directs the proper response and use of transportation-related resources in the most efficient fashion. These specially trained teams provide technical, logistical, and incident management support to the incident commander by establishing necessary traffic control and diversion routes, serving as the liaison for the New Jersey Department of Transportation to mobilize resources, safely and quickly restoring lanes of traffic, facilitating necessary repairs, and reopening the roadway. In addition, IMRT members work with other in-state and out-of-state agencies in planning, coordinating, and implementing traffic remediation efforts for special events such as major sporting and entertainment events.
    • In southeast Florida, the Severe Incident Response Vehicle (SIRV) program is dedicated to keeping motorists and emergency responders safe during traffic incidents while working to quickly clear the roadways. Program personnel respond to severe traffic incidents such as full highway closures, fatalities, overturned commercial trucks, and any other event that may last longer than 2 h. (6) The SIRV vehicles carry additional equipment and supplies to provide a higher level of traffic maintenance than that supported by the Road Ranger service patrol vehicles.
  • End-of-queue advance warning systems. Static, arrow board, or dynamic message signs are commonly utilized to warn approaching motorists of a downstream traffic queue. Arrow boards and DMSs used for this purpose are commonly portable, and mounted on trailers or installed on appropriate response vehicles. End-of-queue advance warning should occur far enough upstream to provide motorists with sufficient notice to slow and stop their vehicle, as necessary. The appropriate location varies depending on the speed limit, extent of congestion, and roadway geometrics that affect driver sight distance. Warning devices should be moved as needed to remain well in advance of the queue. The effectiveness of end-of-queue advance warning systems is dependent upon the nature and extent of traffic control devices available as part of the end-of-queue advance warning system, and the expediency with which these devices are mobilized and deployed.

    End-of-queue advance warning systems are widely used to support TIM operations, predominantly by transportation agencies across the Nation. Of the participants in this investigation, end-of-queue advance warning systems are reported to be in use in Bishop, CA, Los Angeles, CA, Redding, CA, Stockton, CA, Camden, NJ, Chattanooga, TN, and Salt Lake City, UT.

  • Alternate route plans. Alternate routes have the potential to reduce traffic demand at the scene and reduce delay and frustration for the motoring public. Appropriate alternate routes intended for public use are often difficult to identify and require associated diversion plans to be effective. During an incident, motorists may self-route or be directed to an alternate route by response personnel. Not all routes may be able to accommodate all traffic types. Truck traffic requires sufficient infrastructure that can support heavy loads and accommodate larger vehicle dimensions. Bridge and overpass structures are commonly limiting factors along potential alternate routes. In such instances, distinct alternate routes may be identified for passenger car and truck traffic. The designation of alternate routes can be politically charged; buy-in from all affected jurisdictions is required. When county or city roadways are utilized as alternate routes, appropriate jurisdictions should be notified immediately so that they may adjust to accommodate the additional traffic flow.

    Despite these challenges, the 2004 ITS Deployment Survey reported at least 62 major metropolitan areas in the United States with pre-planned alternate route plans serving certain sections of the freeway system. (2) Select examples include the following:

    • In northeast Florida, TIM practitioners developed alternate route plans and distributed these plans, in electronic format, to all TIM agencies. (6)
    • Working closely with local law enforcement agencies, TIM practitioners in Maine and New Hampshire developed a series of alternate route maps that include local routing scenarios with officer locations, barricades, bridge closures, and detour signs for all major highways within their jurisdictions. (6)
    • In New Jersey, personnel from the New Jersey Department of Transportation and State Police act as facilitators for multi-agency groups tasked with developing alternate route plans for all State highways and interstates. To date, plans have been established for 19 of the 21 counties. In a recent related initiative, the DVRPC developed the web-based Interactive Detour Route Mapping (IDRuM) application, accessible at www.idrum.us, which currently includes existing regional emergency route plans for New Jersey and Pennsylvania. The IDRuM application is available both online and offline, with the offline version designed to give TIM personnel access to the alternate routes where Internet access is limited or nonexistent. The ultimate goal is to integrate New Jersey’s alternate route plans into IDRuM for statewide application.
    • In Wisconsin, a statewide template was developed to lend consistency when establishing and signing for emergency alternate routes. (6)
    • To lend consistency to operations when implementing alternate route plans, a real-time, knowledge-based decision support tool—Traffic Control Manager—was used to assist TMC personnel in Anaheim, CA, with selection of alternate route plans and associated traffic signal control timing plans after the occurrence of an incident. Simulations indicated that the plans chosen by the decision support tool reduced average travel time 1.9 to 29 percent and reduced stop time 14.8 to 55.9 percent, compared to scenarios without the tool. (41)

    Common criteria for initiating traffic diversion to alternate routes are based on the type of incident (reported by 56 metropolitan areas), incident duration (reported by 59 metropolitan areas), incident location (reported by 53 metropolitan areas), number of freeway lanes blocked (reported by 55 metropolitan areas), and time of day (reported by 36 metropolitan areas). (2)

    Sufficient personnel, traffic control devices, and signing are required to adequately convey diversion direction to the motoring public who are being asked or required to divert. More information on developing and implementing alternate route plans is available in FHWA’s Alternate Route Handbook, accessible at https://ops.fhwa.dot.gov/publications/ar_handbook/. (42)

Quick Clearance and Recovery

Clearance and recovery are the final steps in the TIM process. Clearance refers to the safe and timely removal of any wreckage, debris, or spilled material from the roadway. Recovery refers to the restoration of the roadway to its full capacity. It is important to recognize that when providing information to the motoring public, motorists are most interested in their chances of encountering delay—an incident should not be publicly reported as “cleared” until the traffic backup has fully cleared. If an incident has been reported cleared because the blockage has been removed but motorists encounter significant delay in the traffic backup, an agency may lose credibility and the public’s trust and respect.

The objectives of improved incident clearance and recovery are to restore full roadway capacity as quickly and safely as possible; enhance the safety of responders and motorists; make the most efficient use of resources, including equipment and personnel; and minimize delay and ease frustration for motorists. Effective incident clearance relies on effective equipment utilization (i.e., appropriate towing and recovery vehicles, push bumpers, etc.) and an awareness of legal authority to speed clearance.

Common challenges to effective quick clearance and recovery relate to the following:

  • Abandoned vehicle hazards. When a vehicle becomes disabled because of a mechanical failure, gasoline depletion, flat tire, or some other reason, motorists seldom stay in their vehicle and wait for help. Many walk along the roadway shoulder or are transported by another passing vehicle to reach services. When responders stop to offer assistance and a motorist is not with a vehicle, their action is commonly limited to “tagging” the vehicle as abandoned (if the responder has that authority). Once a vehicle has been tagged as abandoned, motorists are allowed to leave a vehicle in its location often in excess of 24 h and up to 72 h. Results of the 2004 ITS Deployment Survey indicated that 47 percent of participating metropolitan areas allow abandoned vehicles to remain in the right-of-way for more than 24 h. (2) Sometimes vehicles remain on the shoulder of the roadway longer than the allowable time either because they were not detected and reported immediately by law enforcement personnel, or law enforcement personnel did not specifically check for the vehicle at the end of the allowable time period. Accurately enforcing the “time clock” requires vehicles to be tagged at the time of detection and shoulders to be actively patrolled to assure that vehicles are not left long beyond the time allowed.

    Law enforcement personnel can typically expedite removal of abandoned vehicles that are deemed a hazard; negative public reaction to this action and competing law enforcement duties may limit this practice despite the safety risk. In 2005, North Carolina completed a 5-yr study of abandoned vehicle crash involvement and found that a total of 1,300 abandoned vehicles were struck, resulting in 47 fatality crashes and over 500 injuries. (43)

  • Lengthy minor incident clearance. Minor incidents, the most frequently occurring type of incident, typically affect only the roadway shoulder, result in local traffic impacts, require response from a single agency or company, and require informal actions to be taken to clear the incident. Some minor incidents may be cleared by the party involved before a responder even arrives at the scene. These self-helped incidents are seldom reported to law enforcement agencies.

    Few direct operational challenges exist when clearing minor incidents. Instead, the factors challenging the quick clearance of minor incidents tend to be institutional in nature. For example, response to minor incidents may be low in priority relative to other competing duties that must be performed by law enforcement or transportation agency personnel. Consequently, response times to minor incidents may be lengthy, particularly in areas where dedicated service patrol programs are not offered. Secondly, quick clearance of minor incidents may be restricted by current legislation or policy that prevents an unattended or abandoned vehicle from being immediately removed from the roadway. Minor incidents can also be perceived to be major incidents if responders lack adequate training. For example, incidents involving hazardous materials are often classified as major incidents because they require response from specially trained fire or hazardous material response personnel. Minor petroleum, antifreeze, or other noncargo fluids spilled from the vehicle do not constitute a hazard; unnecessary clearance delay often results because responders incorrectly classify them as hazardous materials. (19) Delayed clearance of minor incidents increases the amount of time that response personnel are exposed to danger; the potential for secondary incidents; and motorist delay, associated fuel consumption, and harmful emissions.

  • Lengthy major incident clearance. Major incidents typically affect one or more of the travel lanes, result in area-wide or corridor-wide traffic impacts, require response from multiple agencies or companies, require a more formal response plan, may involve fatalities or hazardous materials, and may require investigation. Major incidents occur less frequently but produce more severe impacts.

    A myriad of factors may challenge the quick clearance of major incidents. Response personnel from multiple agencies or companies must not only perform the duties for which they were trained quickly and effectively, but must also coordinate these activities among all responders in the context of the broader incident management process. Oftentimes, this coordination suffers because of technical and institutional inefficiencies in communications. Major incidents also often require response from specially trained responders (i.e., responders capable of performing accident investigation or hazardous material response and cleanup) and specialty equipment (i.e., rotating crane, front-end loader, etc.) that may be slow to mobilize. In either case, a lack of consensus regarding the importance of quick clearance among all response agencies will exacerbate the detrimental incident impacts.

  • Liability concerns. Perhaps the most common issue that arises when attempts are made to speed incident clearance is the fear of liability resulting from additional damage to a vehicle or its cargo because of clearance actions taken. Important points to realize, however, are that:

    • The vehicle and cargo are already damaged as a result of the incident and are already, in many instances, unusable.
    • Damage costs are most often covered by insurers, not the party involved.
    • Liability costs attributable to extra damage are negligible in comparison to the liability costs associated with an unnecessary fatality or serious injury as a result of a secondary incident.

Table 5 identifies the various tools and strategies that have proven effective in overcoming each of these challenges and identifies select locations where these tools and strategies are in use.

Table 5. Quick clearance and recovery challenges, strategies, and select implementation locations.
QUICK CLEARANCE AND RECOVERY STRATEGIES Abandoned Vehicle Hazards Lengthy Minor Incident Clearance Lengthy Major Incident Clearance Liability Concerns EXAMPLE APPLICATIONS
Abandoned Vehicle Legislation/Policy No Value No Value No Value 21+ U.S. Metropolitan Areas, IN, NC
Safe, Quick Clearance Laws—Driver Removal No Value No Value No Value ~25 States, including FL, GA, MD, NC, OH, SC, TN, TX, VA, WI
Service Patrols No Value No Value No Value 130+ U.S. Metropolitan Areas, AZ (Phoenix), CA, FL, GA (Atlanta), IN, MD, MN, NM (Albuquerque), OR, TN, UT (Salt Lake City)
Vehicle-Mounted Push Bumpers No Value No Value No Value CA (Redding, Stockton), MD (Baltimore), NJ/PA (Delaware Valley Region), OH (Cincinnati), TN (Chattanooga), TX (Austin), UT (Salt Lake City)
Incident Investigation Sites No Value No Value No Value 16+ U.S. Metropolitan Areas, TX (Houston)
Safe, Quick Clearance Laws—Authority Removal No Value AZ, CA, CO, FL, GA, IL, IN, KY, MO, NM, NC, OH, OR, SC, TN, TX, VA, WA
Quick Clearance/Open Roads Policy No Value No Value 35+ U.S. Metropolitan Areas, CA, FL, GA, ID, IN, LA, MD, NV, NH, TN, UT, WA, WI
Non-cargo Vehicle Fluid Discharge Policy No Value No Value FL, MN
Fatality Certification/Removal Policy No Value No Value No Value PA, TN, TX (Austin), WA
Expedited Crash Investigation No Value No Value No Value 93+ U.S. Metropolitan Areas, FL, IN, TX (North Central Region), UT
Quick Clearance Using Fire Apparatus No Value No Value No Value TX (Austin)
Towing and Recovery Quick Clearance Incentives No Value No Value No Value FL, GA, WA
Major Incident Response Teams No Value No Value No Value DE, FL, IL (Chicago), LA, MD, NJ, OH (Cincinnati, Columbus), NY, TX (Dallas Co.), WA

Additional descriptive information regarding the various tools and strategies and select locations where these tools and strategies are in use is provided below.

  • Abandoned vehicle legislation/policy. Given the similar risk for being struck by passing motorists, supporting legislation that does not distinguish response personnel removal actions for attended or unattended/abandoned vehicles is most advantageous for speeding the clearance of minor incidents. For example, North Carolina law supports the immediate clearance of any abandoned vehicle on the paved roadway or shoulder on any State-maintained roadway. In addition, through a memorandum of understanding between the North Carolina Department of Transportation and the City of Greensboro, Incident Management Assistance Patrols (IMAPs) are allowed to impound or tow any abandoned vehicles off the roadway shoulders using the city’s towing rotation procedures. (6)

    As an alternative, States can modify existing legislation specific to unattended/abandoned vehicles to reduce the amount of time that motorists are allowed to leave a vehicle in its location. Indiana recently passed a law that reduced the amount of time that an abandoned vehicle is able to remain in the right-of-way from 72 h to 24 h. (6) Comparatively, the 2004 ITS Deployment Survey reported at least 21 major metropolitan areas in the United States having associated State laws that limit the amount of time unattended/abandoned vehicles are allowed to remain within the State right-of-way to between 0 and 4 h. (2)

    More information regarding supporting legislation for abandoned vehiclescan be found in FHWA’s Traffic Incident Management Quick Clearance Laws: A National Review of Best Practices, accessible at https://ops.fhwa.dot.gov/publications/fhwahop09005/index.htm. (39)

    A third strategy that may not require a change in existing legislation is to expand the definition of “hazard” to include unattended/abandoned vehicles on the roadway shoulder or median. In most areas, responders can legally remove any parked vehicle that is considered hazardous. Because the perception of a “hazard” varies widely among responders, removal of unattended/abandoned vehicles on the shoulder or median may not be consistently performed. Agreement between law enforcement, transportation, and other response personnel regarding what constitutes a hazard can encourage improvements in quick clearance in the absence or interim of legislation change.

    Driver education can encourage motorist compliance with laws and/or policies related to abandoned vehicles. When a vehicle becomes disabled, motorists frequently leave their vehicle unattended to obtain services. In the absence of or in conjunction with legislation that requires motorists to remain with their vehicle, driver education efforts can encourage motorists to stay with their vehicles to hasten vehicle repair, accommodate towing, and minimize traffic impacts. With extensive use of service patrols, law enforcement patrols, cellular telephones, and traffic-reporting services in most major metropolitan areas, quick and efficient notice of incapacitated vehicles is enhanced. A significant incentive for motorists is that, by staying with their vehicle and receiving help from law enforcement, transportation, or publicly or privately sponsored service patrol programs, they may save money. Many motorist assistance services are free or require a nominal charge.

  • Safe, quick clearance laws—Driver Removal. Driver Removal laws—also referred to as Fender Bender, Move It, or Steer It/Clear It laws—are considered key strategies for speeding clearance of noninjury, property-damage-only crashes, which account for the majority of all crashes on U.S. roadways. These laws, currently enacted in approximately half of all States, encourage or require drivers involved in incidents to move their vehicle out of the travel lanes if they can do so safely. In the case of an immobilized vehicle, Driver Removal laws commonly mandate that drivers immediately seek assistance to remove their vehicle from the travel lanes. Concurrent legislation or language that protects drivers from liability resulting from their actions (in the absence of gross negligence) or waives at-fault determination regarding the cause of the incident as a result of moving their vehicle is often included to encourage drivers to expeditiously move their vehicle.

    Driver Removal laws are becoming more important over time. As the levels of congestion build on U.S. roadways, transportation and law enforcement personnel meet increasing TIM demands, in the context of their other duties and responsibilities. Public agencies are challenged to function with ever-increasing constraints on personnel and resources. Driver Removal laws that require drivers to take response action not only enhance the safety of those involved and of approaching motorists, but also allow transportation and law enforcement personnel to focus on other duties. The effectiveness of Driver Removal laws is dependent upon motorist awareness of their responsibilities under this law and associated enforcement actions to ensure that the law functions as intended.

    Several States have developed publicity materials to raise awareness of driver responsibilities under Driver Removal laws (see table 6). Using an alternate approach, the Tennessee Department of Transportation installed more than 100 signs at key locations along the State’s urban freeway system with the message “Move Damaged Vehicles to Shoulder If No Serious Injury.” (9)

    Table 6. Example of Driver Removal law publicity materials.

    Hamlin et al. considered the benefits attributable to a Driver Removal law enacted in South Carolina. (44) Microscopic simulation analysis estimated that implementation of the related legislation resulted in an 11 percent reduction in delay for minor incidents with one lane blocked. This reduced delay, in turn, resulted in an average cost savings of $1,682 per incident, which is significant when considering the number of minor incidents occurring on a daily basis in large metropolitan areas. Besides the effect on congestion and its associated impacts, the authors cited benefits related to the safety of road users and incident response personnel.

    More information regarding Driver Removal laws, including recommendations for model language, can be found in FHWA’s Traffic Incident Management Quick Clearance Laws: A National Review of Best Practices, accessible at https://ops.fhwa.dot.gov/publications/fhwahop09005/index.htm. (39) In addition, a recent FHWA educational outreach initiative aimed at encouraging the adoption and effective implementation of safe, quick clearance laws, including Driver Removal laws, is described in Educational Outreach for Safe, Quick Clearance (SQC) Laws and Policies, accessible at https://ops.fhwa.dot.gov/publications/fhwahop10012/tim_sqc.pdf. (40)

  • Service patrols. Service patrols are universally accepted as the most effective tool for TIM. (26) The Federal Highway Administration is currently promoting use of full-function service patrols on all urban freeways on a 24/7 basis as full emergency response partners with law enforcement, fire and rescue, EMS, and towing responders, and is encouraging their sustainability by promoting public agency cost sharing and public/private partnerships. (45) One example of such a public/private partnership exists in Pennsylvania where the Pennsylvania Turnpike Commission has partnered with State Farm Insurance to provide service patrols along designated routes. A similar arrangement with State Farm Insurance exists in Atlanta, GA.

    Service patrols are popular in urban areas across the United States largely because of the flexibility in services offered, hours of operation, cost, and other considerations. Service patrols can be publicly operated by transportation or police departments or privately operated; can operate 24 h a day or only in the peak period; and may rove highway corridors or be stationed at fixed points such as at tunnel entrances, bridge approaches, or elevated roadway sections. Service patrol vehicles commonly include vans or small pickups, but also include heavy-duty large trucks. An estimated 130 distinct service patrol programs operate along U.S. freeways. (46)

    Examples of service patrol programs across the Nation include the following:

    • The Arizona Local Emergency Response Team (ALERT), operated by the Arizona Department of Transportation, provides TIM on freeways in the Phoenix, AZ, metropolitan area, while the Maricopa County Regional Emergency Action Coordinating Team (REACT) provides TIM on arterial roadways.
    • Both California and Florida operate extensive, statewide service patrol programs. In California, the Freeway Service Patrol (FSP) program is funded through combined State and local funds, with local funds originating from a $1 annual vehicle registration fee in participating counties. In Florida, Road Rangers operate in each of the seven Florida Department of Transportation districts and along the turnpike to facilitate quick incident clearance.
    • In Atlanta, GA, the Highway Emergency Response Operators (HERO) program is jointly supported through Federal Congestion Mitigation and Air Quality (CMAQ) funds and private sponsorship by State Farm Insurance.
    • As part of the broader Coordinated Highways Action Response Team (CHART) program, the Maryland State Highway Administration operates an Emergency Traffic Patrol (ETP) program to provide emergency motorist assistance and relocate disabled vehicles out of travel lanes.
    • In Minnesota, the Freeway Incident Response Safety Team (FIRST) has expanded over time to now include 11 routes and 220 mi of metropolitan area freeways.
    • In Tennessee, the Tennessee Department of Transportation initiated the HELP program in 1999 in Knoxville and Nashville. Since that time, the program has expanded to Chattanooga and Memphis and covers more than 180 mi of highways in the four cities. (9)

    Benefit-to-cost ratios for service patrol programs are variable, reflective of the range of reported operating conditions among programs. Consistently, however, the program benefits significantly outweigh the costs. Early benefit-to-cost ratios, reported between 1990 and 1996, range from 2:1 to 36.4:1. (47) More recent benefit-to-cost ratios range from 4.6:1 to 42:1, with a median benefit-to-cost ratio of 9.99:1 and an average benefit-to-cost ratio of 13.3:1. (46) Service patrol benefits most commonly include reductions in overall incident duration, secondary incidents, and delay, including associated fuel consumption and harmful emissions, attributable to their role in responding to and clearing minor incidents and providing scene protection during major incidents.

    As a result of service patrols, overall incident duration has reportedly been reduced by:

    • 28.6 percent in Maryland. (48)
    • 12 to 36 percent in Salt Lake City, UT. (49)
    • 8 min for disabled vehicles in Minneapolis, MN. (50)

    Oregon reported a reduction in incident duration of 15 to 30 percent as a result of expanding its freeway service patrol program from part-time to full-time operations. (51) During the first year of operations at the “Big I” work zone in Albuquerque, NM, the use of on-site service patrols reduced the average incident response time to less than 8 min. (52)

    Once on-scene, service patrol operators can quickly verify the incident, provide scene protection, request additional response that may be required, and establish traffic control as necessary, easing access to the scene for subsequent responders and enhancing on-scene safety:

    • Atlanta, GA, reported a 69 percent reduction in secondary incidents and a related annual cost savings of $1,611,054. (53)
    • Maryland reported a 28.6 percent reduction in average incident duration, leading to an estimated 377 fewer secondary incidents. (48)
    • Northwest Indiana reported an annual cost savings of $618,200 attributable to a reduction in secondary incidents. (54)

    Reported benefits related to delay, including associated fuel consumption and harmful emissions, are also substantial:

    • Atlanta, GA, reported saving 7.25 million vehicle-hours of delay over 1 yr with an annual cost savings of $152,053,180. An associated reduction in gasoline consumption of 5.17 million gallons and a reduction in diesel consumption of 1.66 million gallons was estimated to save an additional $10,365,969 annually. Harmful-emission reductions of 2,457 tons of carbon monoxide (CO), 186 tons of hydrocarbons (HC), and 186 tons of nitrous oxide (NOx), with related annual cost savings of $1,247,985, $15,626,587, and $3,368,436, respectively, were also reported. (53)
    • Florida reported eliminating over 1 million vehicle-hours of delay with an associated fuel savings of 1.7 million gallons of fuel. (55)
    • Maryland reported reduced delay of approximately 30 million vehicle-hours with an associated 5-million-gal reduction in consumed fuel. (48)
    • Minneapolis, MN, reported an annual cost savings of $1.4 million attributable to service patrols. (50)
    • Northwest Indiana reported an annual cost savings of $1,241,300 and $78,300 attributable to delay and fuel consumption reductions, respectively. (54)

    Customer satisfaction with service patrol programs is high. Of motorists surveyed, 99, 95, and 97 percent rated the service patrol program as “excellent” in Tennessee, Atlanta, GA, and Minneapolis, MN, respectively. (8,52,49)

    High levels of satisfaction have also been reported by law enforcement agencies. In 2001, the Tennessee Department of Transportation surveyed officers who had firsthand experiences with the HELP service patrol program. Of the 121 officers who responded to the survey, 70 percent rated the overall HELP program as “excellent,” and 25 percent rated the program as “good.” Seventy percent of the officers also reported that they felt safer when a HELP vehicle is present at an incident scene and estimated that the HELP program has reduced the time required to investigate crashes by an average of 31 percent. (9)

    Service patrols can support quick clearance of minor incidents or disablements by directly relocating the vehicle (i.e., using push bumpers or tow straps/chains) from the travel lane or shoulder to a safe refuge, eliminating the delay caused when a tow truck is needed. If a vehicle is simply disabled, service patrol operators may also provide gasoline, water, or minor mechanical repair services to quickly remedy the problem. During major incidents, service patrols provide an important traffic control and scene protection function (i.e., warning and guiding approaching motorists past the incident) that allows emergency and other response personnel to quickly access the scene, focus on performing duties for which they are specially trained without the distraction or concern for traffic control, and rapidly exit the scene to ensure speedy transport of victims to a medical center or to expedite the opening of blocked lanes.

    Additional information regarding the development, implementation, and operation of effective safety service patrols can be found in FHWA’s Service Patrol Handbook, accessible at https://ops.fhwa.dot.gov/publications/fhwahop08031/ffsp_handbook.pdf. (56)

  • Vehicle-mounted push bumpers. Push bumpers, mounted on response vehicles, are used to quickly and safely remove disabled vehicles from the shoulder or travel lanes, reducing the likelihood of secondary incidents and improving the safety of both response personnel and motorists. Push bumpers are commonly mounted on law enforcement and transportation agency vehicles, particularly those used in a service patrol capacity. Vehicles equipped with push bumpers are used to relocate vehicles out of immediate danger; towing and recovery vehicles are used to transport the vehicle longer distances as required.

    Vehicle-mounted push bumpers are widely used to support TIM operations across the Nation. Of the participants in this investigation, vehicle-mounted push bumpers are reported to be in use in Redding, CA, Stockton, CA, Baltimore, MD, the Delaware Valley region in New Jersey and Pennsylvania, Cincinnati, OH, Chattanooga, TN, Austin, TX, and Salt Lake City, UT.

  • Incident investigation sites. Results of the 2004 ITS Deployment Survey indicated that 16 participating metropolitan areas in 12 States utilize incident investigation sites to support TIM operations. (2) Incident investigation sites provide a safe refuge off the main roadway where further investigation or documentation can take place. Sites should be easily accessible from the main roadway, yet sufficiently out of sight to prevent motorist delay caused by rubbernecking. In addition, sites should be adequately signed, be lit, and provide enough space to accommodate multiple vehicles or a large truck.

    In Houston, TX, a brief public service awareness video describing the State’s Steer It, Clear It law directs motorists to relocate their vehicle—if it can be normally and safely driven—to a designated incident investigation site or other safe location to minimize interference with existing freeway traffic. The video is available for viewing at the Houston TranStar website, accessible at http://www.houstontranstar.org/sici.aspx. (57)

  • Safe, quick clearance laws—Authority Removal. Authority Removal laws provide authorization to a predesignated set of public agencies—generally including State, county, and local law enforcement or State departments of transportation—to remove damaged or disabled vehicles and/or spilled cargo determined to be a hazard from the roadway. Driver and authority removal responsibilities may be defined within the same statute: if the driver is unwilling or unable to remove the vehicle or cargo, designated authorities may require or perform removal without the consent of the owner. Authority Removal laws may also include immediate tow-away policies to ensure the timely removal of disabled vehicles from roadway shoulders in highly congested, metropolitan areas. More commonly, separate Authority Tow laws are in place to support removal of incident-involved vehicles and/or cargo on the shoulder or roadway right-of-way to an off-site location (e.g., storage area, service station).

    Large-truck incidents can add a unique challenge to the clearance process. Often, cargo transported by truck is spilled across the roadway, requiring not only the righting and clearing of the involved vehicle but also the cleanup of associated cargo. If the cargo is hazardous, response from specially trained spill response personnel is required. In addition, certain types of nonhazardous cargo—such as agriculture or livestock, or certain other perishable products such as food—may require certification from the Department of Agriculture or Health Department to confirm that the load was damaged and is unusable. Personnel from these agencies are not common TIM participants and as such may be slow to arrive at the scene. Supporting legislation or language that allows for the rapid relocation of nonhazardous cargo out of the roadway prior to their arrival supports quick clearance ideals designed to enhance public and responder safety and reduce delay.

    Further, the effectiveness of Authority Removal laws may be compromised if response personnel are reluctant to exercise their full authority under this law. Often, liability concerns are raised by responding agency personnel when they clear an incident because of additional damage the vehicle or cargo may incur during clearance procedures, even though the resulting additional vehicle damage is often minimal and covered by the causing party’s insurer. Concurrent “hold harmless” legislation or language that protects responders from liability resulting from their actions (in the absence of gross negligence) is often included with Authority Removal laws to encourage responders to expeditiously move damaged or disabled vehicles and/or spilled cargo from the roadway. The same predesignated agencies authorized to remove damaged or disabled vehicles and/or spilled cargo from the roadway, as well as any qualified responder working under the direction of these agencies, are generally protected under these provisions.

    Approximately half of all States have enacted Authority Removal laws, and approximately half of all States that have Authority Removal laws have concurrent hold harmless provisions. For example, Indiana recently passed a law that includes hold harmless language allowing enforcement personnel to safely and quickly remove vehicles or debris from the roadway and reopen the impacted traffic lanes. (6) Select States (Texas and Virginia) also include hold harmless clauses that protect against liability for responder actions not taken; authorities are not held responsible for any damages or claims that may result from the failure to exercise any authority granted, provided they are acting in good faith.

    More information regarding Authority Removal laws and associated hold harmless language, including recommendations for model language, can be found in FHWA’s Traffic Incident Management Quick Clearance Laws: A National Review of Best Practices, accessible at https://ops.fhwa.dot.gov/publications/fhwahop09005/index.htm. (39) In addition, a recent FHWA educational outreach initiative aimed at encouraging the adoption and effective implementation of safe, quick clearance laws, including Authority Removal laws, is described in Educational Outreach for Safe, Quick Clearance (SQC) Laws and Policies, accessible at https://ops.fhwa.dot.gov/publications/fhwahop10012/tim_sqc.pdf. (40)

  • Quick clearance/open roads policy. A key agreement supporting TIM efforts is a quick clearance or “open roads” policy that binds agencies to quick clearance consensus by setting implied or explicit goals for clearing traffic incidents from the roadway. Depending on how it is drafted, quick clearance policies can help to speed the clearance of both minor and major incidents, subsequently enhancing responder and public safety and reducing delay.

    In 2004, the ITS Deployment Survey reported at least 35 major metropolitan areas in the United States having associated policies and procedures facilitating the quick removal of heavily damaged vehicles and nonhazardous cargoes. (2) For example, member agencies participating in Indiana’s Traffic Incident Management Effort (IN-TIME) are required to sign a multilateral working agreement that establishes an “Open Roads Philosophy” to work together to “accomplish improved safety, clearance and communication during traffic incidents and/or obstructions on all public roadways in the State of Indiana.” Through a partnership between the Indiana Department of Transportation and the Indiana Law Enforcement Academy, an accompanying IN-TIME video was produced introducing TIM initiatives in Indiana and showing support for quick clearance. The video features an introduction by the Indiana State Police superintendent and can be viewed at the IN-TIME website, accessible at http://www.indianaquickclearance.org/. (58)

    Other examples of quick clearance policies from across the Nation include the following:

    • Florida’s Open Roads Policy. Local open roads policies are signed by all agencies as an addendum to the statewide Open Roads Policy.
    • Georgia’s Open Roads Policy.
    • Maryland’s Removal of Vehicles from Roadway Interagency Agreement.
    • New Hampshire’s Quick Clearance for Safety and Mobility Interagency Memorandum of Understanding.
    • Tennessee’s Urgent Clearance of Highway Incidents and Safety at Incident Scenes Interagency Memorandum of Understanding.
    • Wisconsin’s Interagency Freeway Incident Clearance Policy Statement.

    Louisiana passed the first-ever open roads law in the Nation that mandates keeping roads open whenever possible, requires TIM training for all law enforcement officers, establishes improved towing procedures, and requires open roads agreements between key agencies. (6)

    The inclusion of explicit performance goals in quick clearance policies helps to ensure continued focus on quick clearance and improvement in operations. The most frequently used performance metric for TIM programs is average or maximum incident clearance time, defined as the time between the first recordable awareness and the time at which the last responder has left the scene. (59) California, Washington, and Florida have statewide 90-min incident clearance targets. Utah’s performance goals are based on incident severity: 20 min for fender benders, 60 min for injury crashes, and 90 min for fatalities. Idaho and Nevada take a similar approach, with a 30-, 60-, or 120-min maximum clearance time, based on incident severity. (59)

    The effectiveness of quick clearance policies depends upon the perceived attainability of and focus placed on local clearance time goals and the extent of commitment among TIM agencies in pursuing these goals. The I-95 Corridor Coalition’s Traffic Incident Management Teams Best Practices Report includes a comprehensive checklist in appendix D for drafting and implementing an effective quick clearance policy. (6)

  • Non-cargo vehicle fluid discharge policy. While some materials pose a danger in any quantity, hazardous materials response procedures are frequently invoked when nonhazardous, non-cargo vehicle fluids are discharged during a minor incident, unnecessarily extending the clearance duration. Spilled vehicle fluids, including crank-case engine oil, diesel fuel, transmission or hydraulic fluids, etc., are generally not considered hazardous wastes.

    Some States have adopted procedures or policies that exempt non-cargo vehicle fluid spills from hazardous materials response procedures, providing the spill has been contained on the pavement. In direct support of their Open Roads Policy, Florida developed Guidelines for the Mitigation of Accidental Discharges of Motor Vehicle Fluids (Non-cargo) to encourage the mitigation of such spills and speed the clearance of minor incidents. (60) Under these guidelines, the Florida Department of Transportation and other incident response personnel may apply absorbents and sweep off travel lanes regardless of spill quantity. The absorbent materials are moved out of the travel lanes and stored at the roadside, or are containerized and placed in the damaged vehicle(s) for removal by the towing company. It is not necessary to await a licensed clean-up contractor.

    Similarly, authority is defined in Minnesota’s Traffic Incident Management Recommended Operational Guidelines. (61) Under these guidelines, Minnesota Department of Transportation personnel are allowed to help contain and clean up non-cargo vehicle fluid spills using absorbent products but must obtain annual “right-to-know” training regarding these materials. The effectiveness of non-cargo vehicle fluid discharge mitigation policies in enhancing the quick clearance of minor incidents was not found to be distinctly reported. Instead, the benefits of such a policy are often combined and reported jointly with benefits attributable to broader quick clearance policies and/or reported only for major incidents.

    The effectiveness of non-cargo vehicle fluid discharge mitigation policies can be compromised if there is a lack of awareness among response personnel and/or reluctance to exercise their full authority under this policy.

  • Fatality certification/removal policy. When responding to fatality traffic incidents, it is important to balance the need for thorough investigations into the cause of death, with the need to minimize responder exposure to danger, minimize risk of secondary incidents involving the motoring public, respect the dignity and privacy of the decedent and the decedent’s family, and restore the flow of traffic.

    In many cases, local policy or State law requires that death be certified by a coroner or medical examiner and that the victim not be moved until the coroner has done so. The result may be significant delays to traffic while the arrival of a coroner is awaited; because the coroner is not facing a life or death situation, he or she may not feel an urgent need to respond. In addition, the number of coroners available is generally limited in comparison to their geographic area of coverage. Alternative policies include allowing a designated EMS unit to certify death. Accordingly, EMS units are typically among the first to arrive at an incident that may involve an injury or a fatality. Vital signs of fatalities can be telemetrically relayed to an off-site coroner for verification, eliminating the need for the coroner to travel to the site. Once death is certified, fatalities can be relocated to a better, safer refuge in the interest of public safety.

    In select States (Pennsylvania, Tennessee, and Texas), Fatality Certification laws permit the removal of the victim before the arrival of the coroner when the incident poses a safety hazard. To expedite clearing the roadway and to prevent additional incidents, law enforcement marks the locations and removes the victims immediately, without waiting for the arrival of the coroner.

    In the absence of or in addition to such legislation, interagency agreements can explicitly define or detail responder operations during fatality incidents. In Texas, for example, the Austin Police Department (APD), Austin Fire Department (AFD), Austin-Travis County EMS, and Travis County Office of the Medical Examiner (TCME) recently developed an agreement that outlines mutual operating procedures to expedite the removal of deceased persons from the scene of an incident when the incident restricts the free movement of traffic on the State and National Highway Systems. The agreement also addresses operating procedures related to the dispatch of and communications with TCME investigative personnel, the expedited transport of deceased persons, the relocation/removal of deceased persons in the absence of TCME investigative personnel, and the maintenance/capture of evidentiary information. Similar agreements are in place between the Washington State Patrol (WSP), WSDOT, and various county medical examiners throughout the State. Incident management personnel in Bellevue, WA, specifically noted the clearance benefits attributable to the removal of a significantly damaged vehicle with the entrapped decedent in the vehicle.

  • Expedited crash investigation. Traditional methods of collecting physical evidence at an incident scene (i.e., the base-tape method, coordinate method, or triangulation method) can be time consuming and personnel intensive, resulting in unnecessary delay to the motoring public and responder risk. Total station surveying equipment (TSSE)—that electronically measures and records the locations of evidentiary items using horizontal distance, horizontal angle, and vertical rise captured simultaneously—was first introduced as a means to speed crash investigation.

    While TSSE is still widely used to support TIM operations, photogrammetry is emerging as a preferred alternative:

    • In a laudable public-public partnership, the Florida Department of Transportation recently procured photogrammetry systems for the Florida Highway Patrol (FHP) statewide. FHP is training two sets of troopers in the photography and software aspects of the systems, respectively, with the goal of converting to a complete photogrammetry-based investigatory process by the end of 2010. (6)
    • Similarly, the Indiana Department of Transportation, Indiana Department of Revenue, Federal Highway Administration, and Indiana Toll Road have cooperatively funded 23 complete photogrammetry systems. Indiana currently has 22 officers and 6 trainers in the State trained in photogrammetry with an average scene-measuring time of 42 min. (6)
    • In a unique application, the Utah Highway Patrol uses aerial photogrammetry to take crash scene photos with a camera mounted on a low-flying, remote-controlled helicopter. (6)

    Photogrammetry captures the necessary data through the process of analyzing and interpreting photos taken at the incident scene. For either system, data captured in the field can be further analyzed off-site using specialized software, reducing the length of time the roadway or lanes need to be closed. Photogrammetry systems have been credited with significantly reducing the amount of time it takes to perform incident investigation while increasing the number of measurements able to be captured.

    To support and encourage the use of photogrammetry, the North Central Texas Council of Governments (NCTCOG) offers a photogrammetry training course as a complement to the region’s Freeway Incident Management series. Two course tracks are offered twice per year to regional law enforcement agencies. Basic training is 5 d in duration and includes a 3-d iWitness™ workshop and a 2-d crash zone workshop. Advanced photogrammetry training is offered over 2 d to students who complete the basic training. Additional information regarding NCTCOG’s photogrammetry training is available through their website, accessible at http://www.nctcog.org/trans/safety/PhotogramTrng.asp. (62)

    In 2007, the ITS Deployment Survey reported at least 93 major metropolitan areas in the United States using these technology-based strategies to expedite crash investigation procedures at major incidents. (2)

    In the absence of technology-based tools, alternative means of marking evidence (i.e., using paint to mark the evidence, including vehicle positions and locations, and a camera to photograph the incident scene) can be used. Once marked and recorded, the incident scene can be cleared. Law enforcement personnel can later return to the incident scene at a time when traffic volumes are low, close the necessary portion of the roadway, and collect the information required as part of the crash investigation. The use of alternative means of marking evidence is also encouraged as a means to speed incident clearance prior to the arrival of technology-based incident investigation tools on-scene.

  • Quick clearance using fire apparatus. Adopting a unique and progressive approach to quick clearance in Austin, TX, the Austin Fire Department recently issued a Special Order that allows AFD personnel to use their on-scene fire apparatus to assist in clearing the roadways. Utilizing tow straps provided by on-scene law enforcement officers, AFD may pull a disabled or blocking vehicle out of the travel lane to the side of the road. Fire and rescue personnel are authorized to act only at the request of a law enforcement officer.

    During minor incidents, this capability is thought to be particularly beneficial when only law enforcement motorcycle units with limited vehicle removal abilities are available on-scene. To make full use of this new operating procedure, local law enforcement agencies are considering equipping all motorcycle units with tow straps. During major incidents, the larger size and towing capacity of the fire apparatus compared to on-scene law enforcement cruisers may prove beneficial in quickly removing larger vehicles involved in the incident from the travel lane. Although benefits attributable to this change in operation have not yet been quantified given its recent implementation, it is anticipated to be highly effective in enhancing the quick clearance of incidents since fire and rescue and law enforcement personnel are typically the first responders to the scene.

  • Towing and recovery quick clearance incentives. A combination of financial incentives for quick clearance and pricing disincentives for slow performance has proven to successfully improve tower performance and reduce clearance times. For example, in 2004, the Florida Turnpike Enterprise implemented the Nation’s first Roadway Incident Scene Clearance (RISC) program in an effort to meet Florida’s open roads policy of clearing incidents from roadways in 90 min or less. Under this program, contract towing and recovery operators are required to respond to major incidents with two certified heavy-duty wreckers and a support vehicle carrying cleanup and traffic control equipment. Contractors earn a $2,500 bonus if they respond to the incident site within 60 min and clear the roadway to traffic within 90 min of the Florida Highway Patrol’s notice to proceed. If the contractor fails to open the roadway within 3 h, the contractor is penalized $10 for each minute over. In the first 9 months of operation, the average time to respond to an incident was 41 min (well under the required response time of 60 min), and the average clearance time was 55 min (well under the required 90 min to receive bonus incentives). (63)

    Georgia and Washington recently initiated similar programs (the Towing and Recovery Incentive Program [TRIP] and the Blockage Buster Tow Incentive program, respectively) aimed at clearing commercial and other vehicle incidents within 90 min. In Georgia, average incident duration decreased from 314 min in 2007 to 131 min in 2008. (64)

    All three programs include explicit equipment, training, and performance requirements for participating towing and recovery companies.

  • Major incident response teams. In a national survey conducted as part of the NCHRP Synthesis of Highway Practice 318: Safe and Quick Clearance of Traffic Incidents, 15 agencies across 9 States reported participating in a major incident response team. (18)

    Major incident response teams are typically comprised of high-ranking individuals from a variety of disciplines (e.g., law enforcement, fire and rescue, and transportation) who train for and respond to major incidents together and who are available 24/7. Major incident response teams not only improve response to an incident scene but also enhance personnel interaction at the scene and support quick incident clearance. Quick clearance efforts benefit from the high level of familiarity among the various team members and their authority to mobilize the necessary personnel and equipment to respond.

    With the advent of the National Incident Management System (NIMS) in March 2004, major incident response teams now have a formalized framework for effective operation. Relying upon ICS principles, NIMS enables responders at all levels from various agencies and jurisdictions to work together more effectively and efficiently to manage major incidents. NIMS also promotes proven incident management practices, standardized personnel training and certification, communications interoperability, ongoing performance evaluation, and more to enhance overall TIM operations.

    Providing a recent example, the New York State Police (NYSP) created a dedicated TIM Detail in 2008 to speed the clearance of major traffic crashes, reduce congestion and secondary collisions, provide more targeted enforcement in crash-prone areas, and fulfill the mandates of New York’s Work Zone Safety Act of 2005. Approximately 100 TIM troopers are deployed statewide. Detail supervisors work with local law enforcement, fire and rescue, EMS, towing and recovery, and other TIM responders to improve the coordination of emergency responses and apply NIMS concepts to the traffic environment. The NYSP TIM Detail strives to achieve the three objectives set out in NTIMC’s NUG: responder safety; safe, quick clearance; and prompt, reliable, interoperable communications. This dedicated-team approach is intended not only to improve the safety of the broader roadway system year-round but also to increase safety in New York’s highway work zones. (65)

September 2010