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Back to Archives | Back to July 2011 Contents 

Traffic Incident Management: Protecting Officers, Saving Lives, and Ensuring the Surface Transportation System’s Efficiency

By Jack Hegarty, Lieutenant Colonel, Arizona Department of Public Safety, Highway Patrol Division

s federal, state, and local budgets shrink and the national economy struggles to leave behind what some now call the Great Recession, transportation infrastructure will likely see modest government investment with only incremental infrastructure expansion. The maintenance and upgrade of the current system of roads and bridges may well require all available transportation infrastructure resources, and overall capacity will likely remain static. Some states are investigating public-private partnerships that may result in new roads and bridges funded by tolls, but this effort is unlikely to add significant interstate miles to the overall system. Most urban areas with major freeways are struggling to maintain aging transportation infrastructure. At the same time, traffic volumes appear to be returning to their highest levels ever recorded. Peak traffic volumes were recorded nationally in 2007 after several years of increases. The Great Recession caused pullbacks in 2008 and 2009, but the second half of 2010 indicated that the United States might be returning to 2007 levels in 2011 and may set a new volume high.1 Congestion, which already is restricting economic growth in major cities and the efficient movement of interstate freight, will increase to historic highs if volumes continue to increase as the national economy slowly recovers.

Surface freight movement and volume undoubtedly will increase in the future. According to the Federal Highway Administration’s (FHWA’s) Freight Analysis Framework version 3, the U.S. transportation system handled the movement of 44 million tons of freight (on average), worth $40 billion, each day in 2009. Forecasts indicate that these numbers will climb to approximately 74 million tons and $108 billion per day by the year 2040.2

This projection estimates freight movement via surface transportation on the nation’s freeway and interstate system will increase more than 2 percent annually over the next 30 years. This gradual increase in surface freight movement in commercial vehicles begins in the same period that most state patrol agencies nationwide are experiencing budget and staff reductions. Some states that make significant contributions to the economy—California, Illinois, Pennsylvania, Florida, and several others—are currently reducing budgets and staff because of state government fiscal constraints. The nation’s state and highway patrols will need to find innovative ways to manage congestion and prevent crashes, given the future outlook for patrol officer staffing.

Congestion-Related Issues

Congestion causes both significant safety and transportation efficiency issues. It produces pollution, creates or magnifies inefficiencies in commerce and business, restricts government operations including homeland security–related functions, and causes traffic crashes. Research has demonstrated that traffic crashes are closely related to traffic volumes and congestion. As the national transportation infrastructure nears capacity in major cities and with the projected increases in volumes, congestion will limit freight movement, increase workforce commutes, and significantly decrease highway safety. All these impacts will significantly increase risks for first responders: police, fire, and medical, as well as towing and transportation workers. The overall economic impact of congestion and the public expense incurred responding to, processing, and investigating traffic crashes could significantly slow economic recovery and growth. This will be especially true in majorportation system. Additionally, the positive trends in fatal crash reduction enjoyed in recent years may be impacted. Secondary crashes, defined by most traffic safety organizations as crashes related to a previous traffic incident and including congestion, other crashes, stranded motorists, lane closures, and traffic enforcement activity, can be as deadly as other types of crashes.

How bad is congestion? The Urban Mobility Report 2010, produced by the Texas Transportation Institute, notes that congestion is worsening and specifically describes some of the impacts:

Congestion is still a problem in America’s 439 urban areas. The economic recession and slow recovery of the last three years, however, have slowed the seemingly inexorable decline in mobility. Readers and policy makers might be tempted to view this as a change in trend, a new beginning or a sign that congestion has been “solved.” However, the data do not support that conclusion.

  • First, the problem is very large. In 2009, congestion caused urban Americans to travel 4.8 billion hours more and to purchase an extra 3.9 billion gallons of fuel for a congestion cost of $115 billion.
  • Second, 2008 appears to be the best year for congestion in recent times; congestion worsened in 2009.
  • Third, there is only a short-term cause for celebration. Prior to the economy slowing, just three years ago, congestion levels were much higher than a decade ago; these conditions will return with a strengthening economy.3

The report further elucidates the following specific detail on the impact of congestion:

Travelers and freight shippers must plan around traffic jams for more of their trips, in more hours of the day, and in more cities, towns, and rural areas than in 1982. It extends far into the suburbs and includes weekends, holidays, and special events. Mobility problems have lessened in the last couple of years, but there is no reason to expect them to continue declining, based on almost three decades of data. See data for your city at

Congestion costs are increasing. The congestion “invoice” for the cost of extra time and fuel in 439 urban areas was (all values in constant 2009 dollars)

  • in 2009—$115 billion;
  • in 2000—$85 billion; and
  • in 1982—$24 billion.

Congestion wastes a massive amount of time, fuel, and money. In 2009:

  • 3.9 billion gallons of wasted fuel (equivalent to 130 days of flow in the Alaska Pipeline)
  • 4.8 billion hours of extra time (equivalent to the time Americans spend relaxing and thinking in 10 weeks)
  • $115 billion of delay and fuel cost (the negative effect of uncertain or longer delivery times, missed meetings, business relocations, and other congestion-related effects are not included)
  • $33 billion of the delay cost was the effect of congestion on truck operations (this does not include any value for the goods being transported in the trucks)
  • The cost to the average commuter was $808 compared to an inflation-adjusted $351 in 1982

Congestion affects people who make trips during the peak period.

  • Yearly peak period delay for the average commuter was 34 hours in 2009, up from 14 hours in 1982.
  • Those commuters wasted 28 gallons of fuel in the peak periods in 2009—two weeks’ worth of fuel for the average U.S. driver—up from 12 gallons in 1982.
  • Congestion effects were even larger in areas with over one million persons—43 hours and 35 gallons in 2009.
  • “Rush hour”—possibly the most misnamed period ever—lasted 6 hours in 2009.
  • Fridays are the worst days to travel. The combination of work, school, leisure, and other trips mean that urban residents earn their weekend after suffering onefifth of weekly delay.
  • 61 million Americans suffered more than 30 hours of delay in 2009.

Congestion is also a problem at other hours.

  • Approximately half of total delay occurs in the midday and overnight (outside of the peak hours of 6 a.m. to 10 a.m. and 3 p.m. to 7 p.m.) times of day when travelers and shippers expect freeflow travel.
  • Midday congestion is not as severe but can cause problems, especially for timesensitive meetings or freight delivery shipments. Freight movement has attempted to move away from the peak periods to avoid congestion when possible. But this accommodation has limits as congestion extends into the midday and overnight periods; manufacturing processes and human resources are difficult to significantly reschedule.4

So while the economic, environmental, and fiscal impact of congestion is significant, the safety impact can be severe. According to the FHWA, approximately 20 percent of all crashes are secondary in nature, and 18 percent of fatalities in traffic crashes result from secondary crashes.5

According to a 1999 National Highway Traffic Safety Administration report, the secondary crashes on the Capital Beltway, which surrounds Washington, D.C., passing through Virginia and Maryland, may account for as much as 36 percent of all crashes:

Stop-Slowing (3,381 crashes; 36 percent). In most cases, the crash report had enough information to assign one of several subgroups of stop-slowing. Typically, congested-related (2,756) crashes show that a lead vehicle slowed or stopped because of congestion, and a following vehicle in the same travel lane did not slow down fast enough to avoid it. In lead-vehicle swerve (113), a vehicle changed lanes in front of a second vehicle and then immediately slowed down and in follow vehicle swerve (118), a vehicle changed lanes coming in behind a vehicle that had already slowed or stopped. These were two maneuvers where a swerving vehicle attempted to avoid a stop-slowing crash in one lane only to become involved in a crash in an adjacent lane.6

It seems reasonable that secondary crashes account for a significant portion of all crashes on major freeway systems. Preventing these crashes is critical to public safety, economic development, homeland security, and first responder safety.

About half of all congestion in major city freeway systems is due to traffic volumes during commute hours, and the other half caused by restrictions on traffic movement due to a previous traffic incident. This unplanned or nonrecurring congestion can cause more crashes and impact efficiency more significantly than the congestion engineers and the first responders anticipate during peak traffic volume hours. The initial traffic incident that causes the nonrecurring congestion could be a crash, a disabled vehicle, debris in the roadway, construction zone activities, a police traffic stop or arrest, or any other occurrence on the roadway that disrupts traffic flow. Aggressively managing this type of congestion—that is, congestion due to another traffic incident—may be the last significant effort that the nation’s transportation engineers, safety professionals, and first responders have to reduce crashes and minimize congestion within a finite surface transportation system.

Crashes due to a previous traffic incident—secondary crashes—not only cause congestion and impact highway safety, they also have the potential to create a cycle resulting in exponential decreases in transportation system efficiency and safety. Each new incident that results in a secondary crash and subsequent congestion can cause an avalanche of further incidents and secondary crashes. Law enforcement and other first responders can limit the impact and stop the cycle with the implementation of a basic Traffic Incident Management (TIM) plan or, even better, a comprehensive plan involving all stakeholders. The safety of first responders and a significant portion of the U.S. national economy and security may well require it.

In Arizona, data have shown how dangerous responding to and investigating crashes and managing traffic incidents on major freeways can be. According to the Officer Down Memorial Page, Incorporated, nine of thirteen Arizona Highway Patrol officers killed in the line of duty since 1990 were killed in traffic crashes. Six of those were killed in secondary crashes; they were managing a traffic incident that had previously occurred.

According to the California Association of Highway Patrolmen, in June 2010 alone, four California Highway Patrol officers were killed in the line of duty. Three of these deaths were the result of secondary collisions: two were traffic stops and one officer was arranging to tow an abandoned vehicle. To the state and the highway patrol officers and troopers, every minute managing a traffic incident on a major freeway or highway can seem like a lifetime.

Managing the Risk

To reduce the risk of injury or death, law enforcement and first responders should develop a system to triage traffic incidents and crashes. Minor crashes and incidents should be moved out of traffic lanes and off the main line quickly. Crashes involving serious injuries or fatalities and other significant investigative scenes will require lane closures and time to process, but these scenes should be worked with a sense of urgency after being properly secured. Some states and jurisdictions have implemented goals, including a 90-minute clearance time for fatal crash investigations. While some in law enforcement will argue that death investigations should not be rushed, the duty to perform a thorough investigation must be weighed against the risk shouldered by a lengthy exposure to high-speed traffic. The likelihood of a secondary crash increases by 2.8 percent for each minute the primary incident continues to be a hazard.7

Police initiated actions—mainly, traffic stops—should be managed appropriately on major freeways. Stop locations should be moved off the main line if possible. Traffic stops in areas where the officer and violator have no safe area, such as against guardrails, barricades, and walls, should be avoided. Motorists experiencing breakdowns should be assisted and moved quickly. Changing a flat tire is not worth anyone’s life.

Traffic enforcement on major freeways can be effectively conducted in areas where shoulders provide adequate safety for traffic stops and when volumes are not excessive. Traffic enforcement is perhaps the most effective crash reduction tool available. It is not without risk, however. Historically, more officers have been killed in the line of duty in traffic crashes than by felonious acts.8

In recent years and months, officers and troopers in several states have been killed on traffic stops in secondary crashes. Even when utilizing best practices and solid officer-safety techniques, traffic stops remain dangerous.

TIM Organizations and Strategies

Several local area organizations and some significant interstate regions use advanced TIM concepts. Probably the best example of a comprehensive and robust TIM organization is the I-95 Corridor Coalition. This coalition was formed about 20 years ago to better manage I-95 corridor issues, including TIM. Law enforcement, fire, medical, towing, and other first responders are fully coordinated during incident management on the corridor. The coalition involves decision makers from the following agencies:

  • state and local departments of transportation,
  • transportation authorities,
  • transit and rail agencies,
  • port authorities,
  • motor vehicle agencies,
  • state police and law enforcement,
  • the U.S. Department of Transportation,
  • the Canadian provincial departments of transportation,
  • intercity passenger and freight transportation providers, and
  • transportation industry associates.9

The I-95 coalition is the best example of a large TIM organization that has had a significant impact on congestion and secondary crashes and is a great model for any group of transportation stakeholders considering forming a TIM partnership in their communities. Another organization that has contributed to the foundation and understanding of TIM is the National Traffic Incident Management Coalition (NTIMC).

The NTIMC is responsible for the National Unified Goal (NUG) regarding TIM. NUG has been adopted by several major traffic safety organizations and is supported by the International Association of Chiefs of Police (IACP),10 and by the FHWA.11 NUG has three simple philosophies:

  • Responder safety
  • Safe, quick clearance
  • Prompt, reliable incident communications12

The NTIMC further describes its strategies and how they relate to congestion, traffic safety, and homeland security.

Improved traffic incident management provides benefits in the areas of congestion relief, responder safety, and domestic emergency preparedness.

Congestion Relief. One-quarter of the traffic congestion in the United States is caused by nonrecurring traffic incidents. While we have learned to function around high levels of recurring congestion during regular peak travel periods, unexpected travel delay is especially destructive to the economy. For every minute that an Interstate lane is blocked during peak congestion, four minutes of travel delay result. Clearing the road quickly requires responders to work together efficiently to accomplish the many tasks involved in traffic incident management: EMS, emergency communications, fire, law enforcement, transportation, towing and recovery, hazmat, public information.

Responder Safety. Responder deaths and injuries are a concern, as “struck-by” incidents happen too frequently. According to the U.S. Bureau of Labor Statistics’ Census of Fatal Occupational Injuries, struck-by-vehicle incidents accounted for 322 fatalities in 2008, 6 percent of all fatal occupational injuries.

Through NTIMC, public safety and transportation organizations join together to promote responder safety policies (such as move-over laws); to encourage the use of new technologies and gear protecting responders during roadside operations; and to promote improved safety procedures and traffic incident responder training.

Domestic Emergency Preparedness. Good traffic incident management is built on strong operational partnerships between transportation and public safety. When we work together side-by-side every day to manage the routine incidents, we build the strong relationships and cooperative policies we need to manage the transportation impacts of major incidents.13

The IACP Highway Safety Committee (HSC) has one concern regarding the NUG: the inclusion of typical traffic incident management applications in the Manual on Uniform Traffic Control Devices for Streets and Highways can be problematic for law enforcement, since this description is not easily defined.14 Police officers encounter new and dynamic situations daily that may result in either a typical solution or an unusual methodology. Traffic incidents are no different. The IACP supports the overriding philosophies in the NUG however, especially the primary focus on first responder safety.

Operation Safe Commute and Communication

Another potential traffic crash reduction tool and TIM program for freeway troopers is the strategic positioning of patrols in areas that are impacted significantly by nonrecurring congestion. Patrol units positioned on freeways systems where they do not interfere with traffic flow can respond more quickly and can clear minor incidents that are close by. Multiple patrols that are either stationary in a beat or roving within a small area on corridors that are the most vulnerable can greatly reduce or even eliminate traffic incidents from causing secondary crashes and congestion.

In Phoenix, Arizona, the Arizona Highway Patrol is experimenting with a proactive approach to clearing minor traffic incidents quickly before they cause secondary crashes. Operation Safe Commute entails assigning patrol officers to a one-mile stretch each of a major freeway during peak traffic hours and empowering them to ensure their stretches of freeway remain clear of incidents that may induce congestion and secondary crashes. Circular patrols and stationary observation of traffic in positions that do not influence traffic flow facilitate this strategy. Quick, safe responses to and quick clearance of minor incidents should prevent secondary crashes and reduce congestion. Weekly and monthly details have been conducted since early 2010 in the Phoenix area and continue. Future research may determine the impact of this effort on crashes and congestion.

Finally, an outreach and communication plan can support a comprehensive TIM program. Educating motorists to exit the main line when experiencing vehicle problems and move from the roadway pursuant to state and local laws that allow or require vehicles involved in minor crashes to leave the main line can improve safety. The Steer It . . . Clear It program in Houston, Texas ( and other similar campaigns can be accompanied with information regarding how dangerous remaining on the main line of a freeway can be.

Resources and Training

The FHWA has developed a TIM workshop available to first responders and managers. The IACP HSC has created a TIM subcommittee charged with investigating effective ways to communicate the dangers of managing traffic incidents and how to best manage the risk.15 The NTIMC website, hosted by the American Association of State Highway and Transportation Officials, has a wealth of TIM resources listed conveniently. The FHWA website also is a great resource for training and TIM background and research.

As traffic volumes increase and first responder agency budgets shrink, the ability to effectively manage traffic incidents, secondary crashes, and the resulting congestion will be significant to any highway safety program. Several critical issues will be impacted: traffic fatalities; local, state, and national economies; homeland security; and the effective and efficient use of our surface transportation system. It will be critical that law enforcement and the first responders to traffic incidents manage those incidents competently and effectively. TIM programs are the last step available in many cases where the roadway capacity and system are finite and the coming decades are sure to bring more commercial and passenger vehicle traffic volume. Only a team effort through a comprehensive TIM program will allow major urban freeway systems to remain safe and effective. ■


1“Key Findings,” INRIX National Traffic Scoreboard, (accessed April 29, 2011).
2“Freight Analysis Framework,” version 3.1 (Fall 2010), U.S. Department of Transportation Federal Highway Administration, Office of Freight Management and Operations.
3David Schrank, Tim Lomax, and Shawn Turner, 2010 Urban Mobility Report, Texas Transportation Institute, The Texas A&M University System (December 2010), 1, (accessed April 29, 2011).
4Ibid, 5.
5Nicholas Owens et al., Traffic Incident Management Handbook, FHWA HOP 10 013 (Science International Corporation, American Transportation Research Institute, January 2010), (accessed April 29, 2011).
6“Urban Interstate Crashes Have Typical Patterns,” National Highway Traffic Safety Administration, (accessed April 29, 2011).
7“Introduction to Traffic Incident Management,” chapter 1 in TIM Handbook table of contents, U.S. Department of Transportation, Federal Highway Administration Emergency Transportation Operations, (accessed April 29, 2011).
8Between 2000 and 2009, 602 officers were killed in traffic crashes (automobile, motorcycles, and struck-by), while 536 were killed feloniously. That is a difference of 66 officers or 12 percent more killed in traffic incidents. Source: Federal Bureau of Investigation, Law Enforcement Officers Killed and Assaulted 2009, October 2010, tables 18 and 63,, (accessed May 11, 2011).
9“What Is the Coalition?,” 1-95 Corridor Coalition, (accessed April 29, 2011).
10Highway Safety Committee, “Contingent Support of the National Unified Goal for Traffic Incident Management,” IACP Resolution adopted at the 114th Annual Conference of the International Association of Chiefs of Police (New Orleans, Louisiana, 2007), (accessed April 29, 2011).
11 National Traffic Incident Management Coalition, “Nation’s Emergency Responders Unite for Safer, Quicker Clearance of Traffic Incidents; Ask Motorists to ‘Slow Down, Move Over,’” press release, November 20, 2007, (accessed April 29, 2011).
12“Objectives and Strategies,” National Traffic Incident Management Coalition, (accessed April 29, 2011).
13“About Us,” National Traffic Incident Management Coalition, (accessed April 29, 2011).
14For more information, please see Richard J. Ashton, “Highway Safety Initiatives: Federal Highway Administration Issues 2009 Manual on Uniform Traffic Control Devices,” The Police Chief 77 (April 2010): 144–146, (accessed May 11, 2011).
15For more information, please see Richard J. Ashton, “New Traffic Incident Management Subcommittee,” Highway Safety Initiatives, The Police Chief 78 (April 2011): 132–134, (accessed April 29, 2011).

Please cite as:

Jack Hegarty, "Traffic Incident Management: Protecting Officers, Saving Lives, and Ensuring the Surface Transportation System’s Efficiency," The Police Chief 78 (July 2011): 30–36.

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From The Police Chief, vol. 78, no. 7, July 2011. Copyright held by the International Association of Chiefs of Police, 515 North Washington Street, Alexandria, VA 22314 USA.

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