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Traffic Incident Management Plan (TIMP)

In 2003, the Average Daily Traffic (ADT) along I-93 ranged from 77,000 vehicles per day north of Exit 5 in Manchester to 114,000 vehicles per day south of Exit 1 in Salem. In addition to the high ADT, traffic incidents have occurred regularly on the stretch of I-93 from Salem to Manchester. The incidents vary in severity, from debris on the Interstate to overturned tractor-trailers, causing motorists to seek detours on local streets, spreading congestion onto the parallel roads. It is evident that a corridor-wide traffic incident management solution has become increasingly critical to keep people and goods moving. The NHDOT, in cooperation with the Federal Highway Administration (FHWA) and regional stakeholders, has sponsored the development of the Interstate 93 Corridor Traffic Incident Management Plan (I-93 TIMP).

The overall vision of the I-93 TIMP is the seamless management of traffic and emergency operations across multiple jurisdictional and agency boundaries for the I-93 Corridor from the Massachusetts Stateline north through Salem, Windham, Derry, and Londonderry to the I-93/I-293 Interchange in Manchester. The plan will be designed to facilitate, as rapidly as practical, clearance of roadways during traffic collisions, natural disasters, special events, and other emergencies, to the extent that this may be accomplished without endangering emergency responders or the public. This coordinated process involves a number of public and private sector partners and entails an identifiable series of activities which may be carried out by personnel from a variety of response agencies and organizations. Those activities fall into seven categories:

  • Detection is the process by which an incident is brought to the attention of the agency or agencies responsible for maintaining traffic flow and safe operations on the roadway.
  • Verification involves confirming that an incident has occurred, determining its exact location and obtaining as many relevant details about the incident as possible, making it possible to dispatch the proper initial response.
  • Motorist information involves various means of disseminating incident-related information to affected motorists.
  • Response includes dispatching the appropriate personnel and equipment, activating the appropriate communication links and disseminating motorist information as soon as there is reasonable certainty that an incident has occurred.
  • Site management is the process of effectively coordinating and managing on-scene resources.
  • Traffic management involves the application of traffic control measures in areas affected by an incident.
  • Clearance is the process of removing wreckage, debris, or any other element that disrupts the normal flow of traffic or forces lane closures, and restoring the roadway capacity to its pre-incident condition.

While many of these activities are inter-related and/or overlap, communication is vital to all. By improving the exchange of information among agencies, the NHDOT, New Hampshire Bureau of Emergency Communications, Emergency Responders and local municipalities can react more effectively to incidents on I-93 to minimize and better manage the impact to local streets and services. Over the past year, the DOT has been working with the communities along I-93 to review and refine the existing I-93 TIMP. The goal is to tailor the existing document by filling in the specific details needed to make the plan fully operational. Development of this plan has included an examination of the primary and secondary parallel alternate routes to I-93, identification of cooperative strategies and technologies that would aid in alleviating congestion, and recommendations for operations and maintenance roles and responsibilities. The I-93 TIMP is the beginning of a multi-stage program for improved traffic incident management, which includes the Transportation Management Center (TMC) and deployment of Intelligent Transportation Systems (ITS) elements. In addition to the already developed I-93 TIMP, NHDOT is looking at ITS and Incident Management Plans that will be developed specifically for the I-93 project corridor during construction. With proper guidance and funding, the I-93 TIMP will evolve into a formal and sustained traffic incident management program.

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