econdary 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