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Back to Archives | Back to July 2012 Contents 

10 TIM Concepts for Reducing Crash Frequency and Seriousness

By Richard J. Ashton, Chief of Police (Retired), Frederick, Maryland; and Grant/Technical Management Manager, IACP

In a perfect world, we could drive from here to there in the actual time required to do so at lawful speeds and in obedience to traffic control signals. However, every commuter knows that we do not live in a perfect world. Drivers and passengers who typically traveled during peak periods in 439 U.S. urban areas spent 34 additional hours in 2010—20 more than in 1982—traveling at congested speeds rather than at free-flow speeds. Further, they wasted 14 gallons of fuel in 2010—8 gallons more than in 1982. The time lost equated to four vacation days and, when coupled with wasted fuel, translated for the average commuter into an expense of $713 in 2010 compared to an inflation-adjusted $301 in 1982.1

Aside from the obvious frustration that traffic incidents evoke in highway users, traffic incidents cause about one-quarter of the congestion on U.S. roadways, and, for every minute a freeway lane is blocked by an incident, four minutes’ travel delay time results.2

An incident is defined in the Traffic Management Data Dictionary, published by the Institute of Transportation Engineers and the American Association of State Highway and Transportation Officials, as “an unplanned randomly occurring traffic event that adversely effects normal traffic operations.”3 It is the nucleus of congestion by which law enforcement and other public safety disciplines are challenged across the United States myriad times every day. To the degree that law enforcement and other disciplines effectively, efficiently, and safely prepare for—and respond to—the primary incident, congestion, as well as the frequency and seriousness of secondary crashes, will be reduced.

A secondary crash is an unplanned event—beginning at the time the primary incident is detected—where a collision that results from the original incident occurs either within the incident scene or within the queue, including in the opposite direction. The likelihood of a secondary crash increases by 2.8 percent for every minute that the primary incident remains a hazard, and secondary crashes alone are responsible for an estimated 18 percent of all freeway fatalities and 20 percent of all collisions.4

Traffic incidents are classified, by virtue of their anticipated duration, into three categories:

  • major—those incidents that are expected to last in excess of two hours;
  • intermediate—those that are projected to last between 30 minutes and 2 hours; and
  • minor—those incidents that are expected to last fewer than 30 minutes.5

Realistically, the bulk of the incidents with which law enforcement deals are the minor ones, such as debris in the roadway, disabled vehicles, fender-bender crashes, and traffic stops. They generally are resolved by a police officer, a tow truck, or a public works vehicle and primarily are of interest only to those directly involved.

However, the traffic incidents that cause the greatest consternation are the major ones, such as crashes involving multiple fatalities or hazmat spills. They often result in lengthy road closures or detours. While they tend to be few and far between, they never are forgotten when they are mishandled—that is, when those delayed by such incidents are late for business meetings, medical appointments, picking up their children from day care providers, long-awaited flights to vacation destinations, or cheering on their children at soccer matches.

Traffic incident management (TIM) is “a planned and coordinated multidisciplinary process to detect, respond to, and clear traffic incidents so that traffic flow may be restored as safely and quickly as possible.”6 Consequently, it is the key to reducing the incidence and the severity of crashes and the congestion and the frustration they create. The three fundamental principles upon which TIM is based—responder safety; safe, quick incident clearance; and prompt, reliable, interoperable communications—are embodied in the National Unified Goal (NUG),7 which the IACP has supported since 20078 and, which it reaffirmed in 2010, except for its continued opposition to the inclusion of “typical traffic incident management applications” in the Manual on Uniform Traffic Control Devices for Streets and Highways (MUTCD).9

To improve the effectiveness with which traffic incidents are approached and resolved, the various disciplines (law enforcement, fire and rescue, emergency medical services, towing and recovery, transportation, public works, and medical examiners) must establish open lines of communication and must anticipate and especially plan for major traffic incidents, uniting their respective expertise into one flexible coordinated response shared by all. Disciplines, especially law enforcement, must move from consecutive to concurrent operations. Multitasking does not mean sacrificing either safety or effectiveness; it simply means not finishing one task before initiating another. For example, a crash investigation does not need to be completed before a tow truck is summoned. The investigating officer often can reduce the incident clearance time10 by requesting a tow truck be dispatched while still completing on-the-scene tasks and by ensuring the correct class of tow truck is sent the first time using the Towing and Recovery Association of America’s TRAA Vehicle Identification Guide, which provides silhouettes of the eight vehicle classes based on gross vehicle weight.11 Likewise, agreements need to be reached—or statutory changes need to be explored—to facilitate the removal of any crash fatality.12 When a fatality occurs on the Phoenix, Arizona, metro area freeway system, the Office of the Medical Examiner for Maricopa County, Arizona, is notified, and its van is diverted from picking up a natural death at a residence to the freeway to reduce the time the highway is blocked.13 Other requests can be handled similarly.

The following are 10 TIM concepts that agencies may wish to consider to reduce the incidence and severity of crashes and the congestion and the frustration they produce:

1. Safety always is paramount. Working on highways is perilous. Even though responders’ hearts are in the right place, they must remain ever vigilant of the dangers that loom at every incident. They must act on the basis of their training and experience to ensure that they can return home safely to their loved ones and live to respond to the next call. However, past experience is a bad omen. During 24 years measured (1987–2010), 278 law enforcement officers were struck and killed by vehicles; this averages out to one officer killed each month. Of these officers, 60 percent were “directing traffic, assisting motorists, etc.,” while the remaining 40 percent were involved in a “traffic stop, roadblock, etc.”14 “Struck by” collisions accounted for 5 of the 87 firefighters killed in 2010, which was almost six percent of firefighter deaths that year.15 Similarly, an average of one on-duty tow truck operator is killed every six days, amounting to more than 60 each year.16

2. Wear high-visibility safety apparel day and night. It’s the law that law enforcement officers directing traffic; investigating crashes; or handling lane closures, obstructed roadways, and disasters on all public roads are mandated to wear high-visibility safety apparel meeting either the Class 2 or 3 ANSI/ISEA 107–2010 standard17 in the American National Standard for High-Visibility Safety Apparel and Headwear or the ANSI/ISEA 207-2006 standard in the American National Standard for High-Visibility Public Safety Vests.18 The public safety vest was purpose designed: It is capable of (1) visually signaling the presence of law enforcement and other public safety officers by contrasting the color and brightness of the vest against the ambient background of the officers’ work environment and (2) including police officers’ requirements for breakaway shoulders; adjustable waists; pen or penlight openings; badge holders; microphone tabs; and side access to such items as pistols, handcuffs, and walkie-talkies.19

All other emergency or incident responders on all public roads also are required to wear high-visibility safety apparel meeting the aforementioned ANSI/ISEA standards, while firefighters and other emergency responders engaged in emergency operations that directly expose them to flame, fire, heat, or hazardous materials may opt to wear approved retroreflective turnout gear.20

The officer on the left is not wearing high-visibility safety apparel. The one on the right is.

3. Size up the scene on approach. “Responders arriving at a traffic incident should estimate the magnitude of the traffic incident, the expected time duration of the traffic incident, and the expected vehicle queue length, and then should set up the appropriate temporary traffic controls for these estimates.”21 Accordingly, a responding officer who recognizes a primary incident as other than minor should notify appropriate superiors who promptly can initiate actions to mitigate its negative impact. For example, additional officers could begin—upstream from the incident—deploying reflectors, road flares, traffic cones, or other channeling devices to taper approaching vehicles away from the incident and into available travel lanes; and motorists could be warned early on of impending delays via media traffic reports, changeable message signs, or other means, so they are able to avoid the affected area. In the event of a major incident, more officers, along with transportation department workers, could begin establishing detours and diverting traffic onto them. Such actions reduce drivers’ frustration, relieve congestion, prevent secondary crashes, and demonstrate that the disciplines involved are working together to alleviate the major incident’s impact.

4. Practice safe parking. Recognizing that the random parking of emergency vehicles at an incident can needlessly divert drivers’ attention from driving, endanger those working the scene, and contribute to secondary crashes, the term “safe-positioned”22 was introduced in the current edition of the
MUTCD to create dialogue between public safety agencies about the desirability of parking emergency vehicles in an organized fashion that promotes the responders’ ability to discharge safely the important tasks at hand and that decreases the likelihood of unnecessarily hampering the flow of traffic. For convenience’s sake, arriving responders often park on the side of the highway opposite the incident or approach the incident from the opposite direction. This entails their moving between passing vehicles, the drivers of which may be rubbernecking. Responders should avoid unnecessary conflict with moving vehicles by parking their vehicles on the same side of the highway as the incident and by approaching the incident from the same direction.

A “lane plus one” response is standard and generally provides a sufficient barrier between the traffic flow and emergency responders during extrication, firefighting, and patient care. Ideally, the blocker vehicle is a fire apparatus that is angled toward the traffic lanes and creates a physical barrier between upstream traffic and the incident scene.23 As conditions improve, the impact on travel lanes should be minimized. For example, a fender bender crash could be moved from travel lanes to the shoulder, and unneeded emergency equipment could be released.

5. Harness new technology. Laser measuring devices, photogrammetry, and total stations show considerable promise in crash investigation by reducing the incident clearance time, limiting officers’ exposure on the highway, and improving accuracy that translates into increased investigative quality and more successful prosecutions. As an example, using photogrammetry, a Florida Highway Patrol trooper spent a total of 18 minutes photographing a 193-foot-long by 127-foot-wide nighttime crash scene that blocked an intersection.24

6. Clear the scene and reopen lanes. The principal strategy surrounding every traffic incident is to respond promptly, secure the scene, treat the injured, investigate the circumstances, and clear the incident in a timely fashion. At the foundation of the NUG’s safe, quick incident clearance principle is a three-pronged solution: an authority removal statute, a driver removal or “move it” law, and a “move over/slow down” law.

Authority removal allows specific responders—usually law enforcement officers—to cause the removal from travel lanes of anything that impedes the free flow of traffic and generally holds those responders harmless from liability except when damage is caused by gross negligence.25 The most basic removal technique is simply driving a vehicle off the highway, followed by installing push bumpers on police cruisers or freeway service vehicles and allowing them to push disabled vehicles off the roadway. In more massive situations, an inoperable large truck or spilled cargo may be pushed off traffic lanes for removal after rush hour, so traffic flow can be restored in the meantime.

Driver removal or “move it” legislation “require[s] drivers involved in typically minor incidents to move their vehicles from the travel lanes, exchange information, and report the crash information as required.”26 When these laws are understood and obeyed by motorists, the involved drivers move to positions of greater safety, and the possibility of secondary crashes and congestion decline.

“Move over, slow down” laws “require drivers approaching a scene where emergency responders are present to either change lanes when possible and/or reduce speed.”27 Even though all states except Hawaii and excluding the District of Columbia have enacted “move over” laws,28 their provisions vary greatly among jurisdictions and tend neither to be publicized nor enforced, regrettably limiting the laws’ effectiveness. Since 2005, the IACP has supported uniformity in these statutes to better ensure the safety of law enforcement officers and other highway workers.29

7. Appropriately reduce lighting. An issue closely related to safe positioning is lighting. More lighting is not always better. Emergency-vehicle lighting “provides warning only and provides no effective traffic control,”30 and its current use does not provide drivers with unambiguous messages. Clearly, the lights of multiple emergency vehicles belonging to various disciplines operating at a single incident are far more likely to mask the message they are attempting to convey, confuse and distract motorists, and endanger responders’ safety than to provide effective direction and order. The MUTCD aptly recommends

[p]ublic 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.31

8. Promote uniformity. To encourage greater cooperation and coordination aimed at resolving incidents more effectively, efficiently, and safely, disciplines need to communicate with each other in understandable ways. Radio codes and other esoteric terms are counterproductive and generate confusion when the NUG’s prompt, reliable, interoperable communications principle is being advocated. Like the TRAA Vehicle Identification Guide described earlier, lane designation terminology, developed by the National Traffic Incident Management Coalition and the TIM Network in 2010, provides a means for all disciplines to describe uniformly and more precisely incident scenes.32 Moreover, the long-sought-after allocation of the D-Block spectrum to public safety, along with $7 billion in funding to build out a nationwide, interoperable, public safety wireless broadband network; a workable governance structure; and preservation of the 700 MHz narrowband mission-critical voice spectrum became a reality in February 2012 when Congress passed—and the president signed—legislation making public safety’s longtime need a reality.33 Finally, cloud computing has the potential of increasing responders’ effectiveness and ultimately reducing costs by sharing in a timely fashion crucial data among the various disciplines at major traffic incidents.34

9. Try new approaches. There may be better ways to resolve traffic crashes or incidents than the way it always has been done. Florida’s Rapid Incident Scene Clearance (RISC) program is but one innovation “to reduce delays associated with the clearance of major incidents.” The RISC program was initiated in 2004 and essentially establishes a 90-minute window for clearing a crash or incident from a limited-access highway, the achievement of which results in the payment to the tow company of the standard $2,500 incentive. Twenty-one tow companies with specialized equipment and personnel expertise currently participate in this program that primarily deals with large vehicles. Basically, a selected tow company must acknowledge a request within 15 minutes, must arrive at the incident scene with all required equipment within 60 minutes of notification, and must clear the scene in 90 minutes. During fiscal year 2011, the RISC program was activated on 89 occasions; the 90-minute clearance time was accomplished 89 percent of the time with an average of 59.3 minutes to reopen all traffic lanes and with a total payment of $221,200.35

The Arizona Highway Patrol’s Operation Safe Commute is another innovative program. On the Phoenix metro area freeway system, where 90 percent of metropolitan Phoenix’s crashes occur, patrol officers are stationed on one-mile stretches during peak traffic hours to ensure the freeway remains clear. “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.”36 During two, three-month periods (October through December 2010, and April through June 2011), roadway clearance times37 were reduced by 30 percent and incident clearance times were reduced by 50 percent.38 There were 4,795 crashes reported on the freeway system during the first three months and 4,366 during the second—a reduction of 9 percent (429 crashes).39

10. Time is of the essence. To the degree that primary traffic incidents are resolved effectively, efficiently, and safely, responders will spend less time on highways and thereby should be exposed to fewer dangers. Further, the likelihood of secondary crashes will decrease and congestion will be reduced.

     Attend the Highway Safety Committee’s Roll-Call Video: Manage to Survive: Traffic Incident Management for First Responders
When: Monday, October 1, 3:30 p.m.–5:00 p.m., in “Coordinated Traffic Incident Management (TIM) Saves Both Time and Lives” workshop
Where: IACP 2012, San Diego Convention Center
Contact: Richard J. Ashton, 1-800-843-4227, extension 276; or
The members of the multidisciplinary TIM Subcommittee40 have worked for the past 18 months to incorporate TIM concepts into the roll-call video Manage to Survive: Traffic Incident Management for First Responders, supported by a cooperative agreement among the U.S. Department of Transportation’s Federal Highway Administration, its Research and Innovative Technology Administration, and the IACP. It will debut at the 119th Annual Conference of the International Association of Chiefs of Police in San Diego, California, September 29–October 3, and is intended to promote cooperation and coordination among the disciplines that respond to traffic incidents in order to achieve the NUG’s objectives.

Time is the common denominator in all successful TIM programs. To the degree that disciplines seek more and better ways to work together concurrently, responder safety will improve, the effectiveness of on-scene operations will be enhanced, and drivers’ frustration will decline. ♦

1David Schrank, Tim Lomax, and Bill Eisele, 2011 Urban Mobility Report, September 2011, 1, (accessed May 17, 2012).
2Nicholas Owens et al., Traffic Incident Management Handbook, FHWA HOP 10 013 (January 2010), 2, (accessed May 17, 2012).
3“Section 2. Review of Literature,” Office of Operations, Federal Highway Administration (FHWA), U.S. Department of Transportation (USDOT), Emergency Transportation Operations, March 31, 2009, quoting the Traffic Management Data Dictionary, (accessed May 17, 2012).
4Owens et al., Traffic Incident Management Handbook, 2, 27, 58.
5FHWA, “Control of Traffic Through Traffic Incident Management Areas,” chap. 6I in Manual on Uniform Traffic Control Devices for Streets and Highways (MUTCD) (2009), 726, (accessed May 17, 2012).
6“Traffic Incident Management,” Office of Operations, FHWA, USDOT, (accessed May 17, 2012).
7National Traffic Incident Management Coalition, National Unified Goal for Traffic Incident Management, November 2007, (accessed February 15, 2012).
8IACP Highway 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 May 17, 2012).
9IACP Highway Safety Committee, “Quick Clearance of Roadway Incidents,” IACP Resolution adopted at the 117th Annual Conference of the International Association of Chiefs of Police (Orlando, Florida, 2010), (accessed May 17, 2012).
10Owens et al., Traffic Incident Management Handbook, 7.
11For more information on the guides, visit (accessed May 17, 2012).
12Owens et al., Traffic Incident Management Handbook, 44–45.
13Captain Jeffrey A. King, Executive Officer, Highway Patrol Division, Arizona Department of Public Safety, email message to the author, March 5, 2012.
14U.S. Department of Justice, Federal Bureau of Investigation, Criminal Justice Information Services (CJIS), Uniform Crime Reports, Law Enforcement Officers Killed and Assaulted [LEOKA] 2010, table 61, (accessed May 17, 2012); LEOKA 2001, table 28, (accessed May 17, 2012); LEOKA 1996, table 23, (accessed May 17, 2012).
15U.S. Fire Administration, Firefighter Fatalities in the United States in 2010 (September 2011), 12, (accessed May 17, 2012).
16“Tow Truck Driver Killed on the Job,” WSVN-TV 7 News, May 11, 2010, (accessed May 12 2012).
17FHWA, “Details for Request 6(09)-4,” MUTCD, April 27, 2010, (accessed May 17, 2012).
18FHWA, “Pedestrian and Worker Safety” and “Flagger Control,” chap. 6D and 6E in MUTCD (2009), 564, 566, (accessed May 17, 2012).
19For additional information, see Richard J. Ashton, “New Federal Rule Seeks to Improve Officer Visibility at Roadside,” The Police Chief 74 (July 2007), (accessed May 17, 2012).
20FHWA, “Pedestrian and Worker Safety,” chap. 6D in MUTCD (2009), 564, 565.
21FHWA, “Control of Traffic through Traffic Incident Management Areas,” chap. 6I in MUTCD (2009), 726.
22FHWA, “General,” chap. 1A in MUTCD (2009), 19, (accessed May 17, 2012); FHWA, “Control of Traffic Through Traffic Incident Management Areas,” chap. 6I in MUTCD (2009), 726.
23State of New Jersey, “Blocker Vehicle,” section 2 in Highway Incident Traffic Safety Guidelines for Emergency Responders (June 1, 2010), 2, (accessed May 17, 2012).
24David A. Templeton, Jr., “Close-Range Photogrammetry for Crash Reconstruction,”, September 23, 2008, (accessed May 17, 2012).
25Owens et al., Traffic Incident Management Handbook, 47; Jodi L. Carson, Traffic Incident Management Quick Clearance Laws: A National Review of Best Practices, FHWA-HOP-09-005 (December 2008), 24–25, 38–40, (accessed May 17, 2012).
26Carson, Traffic Incident Management Quick Clearance Laws: A National Review of Best Practices, 18.
27Ibid., 1.
28“Move-Over laws,”, (accessed May 17, 2012).
29IACP Highway Safety Committee, “Uniformity in ‘Move Over, Slow Down’ Laws,” IACP Resolution adopted at the 112th Annual Conference of the International Association of Chiefs of Police (Orlando, Florida, 2005), (accessed May 17, 2012).
30FHWA, “Control of Traffic Through Traffic Incident Management Areas,” chap. 6I in MUTCD (2009), 729.
32National Traffic Incident Management Coalition, “Lane Designation Terminology,” (accessed May 17, 2012).
33Sam Gustin, “Wireless Windfall,” Time (March 5, 2012),,9171,2107517,00.html (accessed May 17, 2012); Meredith Ward, “A Victory for Law Enforcement: President Signs D-Block Legislation,” Legislative Alert, The Police Chief 79 (April 2012): 8, (accessed May 21, 2012).
34Jennifer Gavigan, “The Cloud Computing Update, Part 1,” Law and Order 59, no. 10 (October 2011), 58–61, (accessed May 17, 2012).
35Florida Department of Transportation Commercial Vehicle Operations and Traffic Incident Management Program, Rapid Incident Scene Clearance Annual Report Fiscal Year 2010/2011 (August 2011),1, 4–9, (accessed May 17, 2012).
36Jack Hegarty, “Traffic Incident Management: Protecting Officers, Saving Lives, and Ensuring the Surface Transportation System’s Efficiency,” The Police Chief 78 (July 2011): 34, (accessed May 17, 2012).
37Owens et al., Traffic Incident Management Handbook, 7.
38Captain King provided these results at the November 30, 2011, meeting of the TIM Subcommittee.
39Captain King provided these statistics at the September 7, 2011, meeting of the TIM Subcommittee.
40Chief Daniel G. Sharp, Oro Valley, Arizona, Police Department, is the Subcommittee Chair. Subcommittee members are Chief Grady T. Carrick, Chief of Research and Special Projects, Florida Highway Patrol; Captain Susan H. Culin, Commander, Traffic Division, Fairfax County, Virginia, Police Department; Commissioner Joseph A. Farrow, California Highway Patrol; Chief Douglas P. Forsman, Champaign, Illinois, Fire Department; Captain Jeffrey A. King, Executive Officer, Highway Patrol Division, Arizona Department of Public Safety; Chief Brian N. Kozak, Cheyenne, Wyoming, Police Department; and Brian W. Purvis, PE, Manager of Roadway Operations, North Carolina Turnpike Authority.

Please cite as:

Richard J. Ashton, "10 TIM Concepts for Reducing Crash Frequency and Seriousness," The Police Chief 79 (July 2012): 48–52.



From The Police Chief, vol. LXXIX, no. 7, July 2012. Copyright held by the International Association of Chiefs of Police, 515 North Washington Street, Alexandria, VA 22314 USA.

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