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Traffic Incident Management Gap Analysis Primer

1. Introduction

A traffic incident is “any non-recurrent event, such as a vehicle crash, vehicle breakdown, or other special event, that causes a reduction in highway capacity and/or an increase in demand[1]. Traffic incidents are a significant cause of congestion delays that motorists encounter every day on roadways and according to the Federal Highway Administration (FHWA), these incidents (ranging from a flat tire to an overturned hazardous material truck) account for about 25% of all non-recurring congestion [2].

Non-recurring incidents dramatically reduce the available capacity and reliability of the entire transportation system and when an incident occurs, congestion quickly builds up and chances of a secondary incident increase. The sooner incidents are detected, the sooner personnel can respond to the incident and clear it from the roadway, thereby allowing traffic lanes to re-open.

A photo of a car accident scene at the side of the highway. An emergency vehicle sits in front of a heavily damaged passenger car. Highway traffic is seen backed up behind the accident.

 Figure 1. Photo. Traffic Incident Management (TIM). [3]

Traffic incident management (TIM) “consists of 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”. Effective TIM reduces the duration and impacts of traffic incidents and improves the safety of motorists, crash victims, and emergency responders. The TIM goals are to:

  • Promote the safety of motorists, crash victims, and incident responders.
  • Reduce the time for incident detection and verification.
  • Reduce response time (the time for response personnel and equipment to arrive at the scene).
  • Exercise proper and safe on-scene management of personnel and equipment, while keeping as many lanes, as possible, open to traffic.
  • Conduct an appropriate response, investigation, and safe clearing of an incident.
  • Reduce clearance time (the time required for the incident to be removed from the roadway).
  • Provide timely and accurate information to the public that enables them to make informed choices.
  • Get traffic moving again as soon as possible after a partial or complete roadway closure while managing the affected traffic until normal conditions are restored.

While individual efforts may be made by various agencies, the overall objective of TIM is to bring these efforts together to formalize a partnership among all agencies. TIM achieves this by coordinating the resources of a number of different entities who represent incident responders as well as private agencies that have a vested interest in TIM, with the mutual goal of reducing the impacts of incidents on congestion, while protecting the safety of on-scene responders and the traveling public.

1.1 The Need for a Primer

One of the most important responsibilities of both State and local transportation and public safety agencies is to ensure the safe and quick clearance of traffic incidents. Traffic incidents pose a significant threat to life safety and influence travel time, economic productivity, and transportation system performance. Effective TIM procedures and advance planning are essential to achieve quick incident clearance without compromising safety for motorists or responders.

Policies and operating procedures for TIM programs not only vary from State to State, but vary regionally within each State and among rural, suburban, and urban areas. Many of the nation’s TIM programs lack a robust, full-scale, comprehensive approach that includes all aspects of incident management with long-term vision and objectives.

For these reasons, an inventory and review of current practices was conducted to analyze the existing capabilities of both the institutional and technical aspects of the national TIM program led by FHWA, as well as those managed by local and/or State governments. This analysis of existing TIM gaps highlighted the need for a primer that outlines a common national structure for TIM programs.

In order to investigate how TIM practitioners currently perceive the need for conducting gap analysis on their respective TIM programs, a TIM gap analysis webinar was conducted in October 2014. More than 50 attendees from various TIM stakeholder groups responded to a series of poll questions. The webinar attendees responded to questions about their self-assessment as well as gap analysis activities, as summarized in Figure 2. It can be seen from the results that although many TIM stakeholders (69%) conduct self-assessments, only 30% have undertaken a gap analysis. These results confirm the need for a TIM gap analysis primer to help guide TIM practitioners in conducting the gap analysis process that will in turn, help to develop a sound traffic incident management program.

Stakeholder Group
Three pie charts: first chart shows percentages of Stakeholder Groups as: 73% Transportation; 12% Law Enforcement; 9% Federal Government; 6% MPOs; 0% EMS, 0% Fire and Rescue; and 0% Towing and Recovery.

Has your agency completed a TIM self-assessment?
Second chart shows percentages if your agency has completed a TIM self-assessment as: 69% Yes and 31% No.

Has your program undertaken a gap analysis?
Third chart shows percentages if your program has undertaken a gap analysis as: 70% No and 30% Yes.

Figure 2. Chart. TIM Stakeholders’ Responses about Self-Assessment and Gap Analysis
(Credit: TIM Gap Analysis Webinar, October 2014)

Based on what was learned during the webinar discussion, it is appropriate to highlight the difference between the “gap analysis” and the “self-assessment” concepts. Although both are used to evaluate the current state of performance and help identify areas of improvement, the gap analysis concept is a more analytical technique which identifies the specific steps needed to reach the desired state of practice. Self-assessment is defined as “a continuing process through which managers at all levels evaluate the effectiveness of their performance in all areas of responsibility, and determine what improvements are required” [4], whereas gap analysis is defined as “a technique that businesses use to determine what steps need to be taken in order to achieve a future state”. It can also be said that gap analysis helps programs to reflect on who they are and ask who they want to be in the future [5].

1.2 Primer Objectives

This document provides guidance to federal, State and local TIM programs and their involved partners on the components needed to develop and sustain a successful full-fledged TIM program. The objectives of this primer are to:

  • Identify and summarize the current state of TIM practice and activities at the national and State/local levels.
  • Identify and summarize gaps found in TIM activities/information for national and State/local departments and agencies.
  • Identify and outline a framework for achieving a complete TIM program for the different levels of government utilizing national guidelines.
  • Outline the key elements that are contained in successful TIM programs.

A key objective for this document is to address the actual challenges that different TIM stakeholders with varied levels of responsibility face in their current TIM practices on a day to day basis.

1.3 Target Audience

The information contained within this document is geared towards multidisciplinary TIM stakeholders from both the public and private sectors. This includes but is not limited to personnel from transportation agencies, law enforcement, fire and rescue, emergency medical services (EMS), public safety communications, emergency management, towing and recovery, hazardous materials (HazMat), utilities, contractors, and traffic information media.

The target audience for this document includes staff responsible for incident response coordination along with executive decision makers who develop and promote incident management policies, plans, and programs. For technical staff, this primer is useful in detailing the step-by-step procedures used for incident management and an effective TIM response. For executive decision makers, this guidance document is useful for conveying the most practical and effective TIM programs and policies, and the steps and resources needed to implement these programs/policies.

1.4 Primer Organization

The content of this primer is divided into six chapters as follows:

Chapter 1: Introduction

Provides an overview of this document including the motivation behind its development and the topic areas discussed.

Chapter 2: TIM Gap Analysis Summary

Summarizes the results of the TIM Gap Analysis conducted and describes the elements needed to develop a successful TIM program.

Chapter 3: Components of Successful TIM Program

Outlines the various components necessary to achieve a mature TIM program that is both effective and sustainable.

Chapter 4: Roles and Responsibilities of TIM Stakeholders

Identifies the roles and responsibilities of each TIM stakeholder and the level of involvement needed by each agency in individual TIM components.

Chapter 5: TIM Program within Transportation Operations Program

Provides an overview of the major organizational areas within a typical State DOT that need to play a role in supporting a comprehensive TIM program. It also identifies key transportation operations staff and their functional roles that are needed to implement and support the program. A case study of the success of the New York State (NYS) TIM program is discussed in Section 5.4 of this document.

Chapter 6: Conclusions and Recommendations

Provides a summary of the important findings in this document, including a summary of the implementation of a successful TIM program.

1.5 TIM Overview

To better understand the complexity of TIM it is best to analyze the eight stages of the TIM process as depicted in Figure 3:

  1. Detection.
  2. Verification.
  3. Response.
  4. Scene Management.
  5. Traffic Management.
  6. Motorist Information.
  7. Clearance.
  8. Recovery.

A chart shows the relative timeline and sequence of the major stages that comprise traffic incident management. At the far left, Detection is shown as the initial stage. The Verification stage then begins and continues towards the right to the mid-point in the chart. The Response, Clearance, and Site Management stages all begin after Verification has begun. Response ends just after Verification ends. Clearance continues to approximately the two-thirds point on the chart. Site Management continues to approximately the three-quarters point on the chart. The Recovery stage is shown as the last, beginning just before the Clearance stage ends. The Traffic Management / Motorist Information stage occurs throughout, from the beginning of Detection to the end of Recovery.

Figure 3. Chart. Timeline of Stages in the TIM Process [6]

The following are descriptions of each TIM stage as well as the TIM methods used during each stage.

  1. Detection – determines that an incident has occurred and is brought to the attention of the agency/agencies responsible for maintaining traffic flow and safe operations on the facility. Various methods of detection include:
    • Cell phone calls from motorists.
    • Closed-circuit television (CCTV) images viewed by traffic management center (TMC) operators.
    • Electronic detection (video processing, radar, induction loops) with traffic incident detection algorithms.
    • Police/service patrols.
    • Calls from public works crews.
    • Motorist aid telephones and call boxes.
  2. Verification – confirms that an incident has occurred, determines its exact location, and obtains as many relevant details about the incident in order to dispatch the proper initial response. Methods used to verify an incident include:
    • Field units (e.g., police, service patrols) at the incident site.
    • CCTV images.
    • Communication with helicopters operated by police, media, or information service providers.
    • Combining information from multiple cellular calls.
  3. Response – dispatches the appropriate personnel and equipment, and activates the appropriate communication links and motorist information media as the incident is verified. Timely and effective response reduces the incident’s duration, and therefore, the time of roadway operation at reduced capacity. In addition to on-scene response personnel, response also includes:
    • Response vehicles that include capabilities such as a mobile communications platform, global positioning system (GPS), and other features to facilitate efficient response.
    • Personnel and logistics support.
    • Interagency response planning and mutual-aid agreements.
    • Intra-agency and interagency communications.
  4. Scene Management – effectively coordinates and manages on-scene resources. Effective scene management increases safety for crash victims, motorists, and responders; coordinates responder activities; and decreases the impacts of an incident on the roadway system. Examples of scene management activities include:
    • Accurate assessment of incidents.
    • Proper establishment of priorities.
    • Use of an Incident Command System (ICS) and Unified Command Structure (UCS).
    • Notification and coordination with appropriate agencies and organizations.
    • Proper placement and staging of response vehicles at traffic incident scenes.
  5. Traffic Management – applies traffic control measures onsite and in areas affected by an incident. Effective traffic management minimizes traffic disruption while maintaining a safe workplace for responders and reduces the likelihood of secondary crashes. Examples of traffic management activities include:
    • Establishment and operation of alternate routes.
    • Use of cones, flares, warning signs, arrow boards, portable dynamic message signs (DMS), and other traffic control resources.
    • Use of traffic control devices such as DMS, highway advisory radio (HAR), ramp meters, and traffic signals.
    • Queue management to actively monitor the end of a queue and warn approaching motorists.
    • Reduction of long-term traffic incident duration.
  6. Motorist Information – disseminates incident-related information to affected motorists through the use of various methods including:
    • Dynamic message signs (DMS).
    • Highway advisory radio (HAR).
    • Commercial radio and television broadcasts.
    • Telephone information systems (i.e., 511).
    • In-vehicle or personal digital assistant (PDA) information.
    • Information service providers (ISP).
  7. Clearance – removes wreckage, debris, or any other elements that disrupt the normal flow of traffic. Improved traffic incident clearance procedures has many positive effects including the ability to:
    • Minimize motorist delay.
    • Make effective use of all resources.
    • Enhance the safety of responders and travelers.
    • Protect the roadway and private property from unnecessary damage during the removal process.
  8. Recovery – evaluates the long-term impact of an incident and identify recovery actions needed to mitigate those impacts. The goal of recovery is to restore the roadway capacity to its pre-incident condition and includes these actions:
    • Restore traffic flow.
    • Restore pre-incident capacity quickly and safely.
    • Debris clearance.
    • Damage assessments.
    • Restoration of damaged infrastructure.
    • Structural inspections [6].

The impact of an incident typically occurs on the local network but can also extend to the regional network.

It should be noted that Figure 3 is obtained from the Freeway Management and Operations Handbook [6] which was published in 2003. Subsequent evolution in TIM community experience on this subject have resulted in revised thinking regarding the TIM elements and their relative timing, especially with regard to the development of TIM performance measures (PM).

A more recent understanding of the traffic incident elements and timeline was developed by the USDOT ITS Joint Program Office (ITS JPO) [7] and is depicted below in Figure 4, with the key incident times summarized in Table 1.

A chart shows a timeline with markers indicating key activities and phases after an incident occurs. T zero to T seven indicate the time to return to normal flow. At T zero, the incident occurs. The detection phase begins. At T one, the incident is reported, the detection phase ends, and the verification phase begins. The roadway clearance and incident clearance phases begin. At T two, the incident is verified. The verification phase ends and the response phase begins. At T three, response is identified and dispatched. At T four, response arrives on the scene and the response phase ends. At T five, all lanes are open to traffic and the roadway is cleared. The roadway clearance phase ends. At T six, response departs the scene and the incident is cleared. The incident clearance phase ends. At T seven, normal flow of traffic returns.

Figure 4. Chart. Timeline of Traffic Incident Elements [7]

Table1. Key Traffic Incident Times [7]

Measure Definition
Detection Time
T1 – T0
Time between the incident occurring and the incident being reported. Detection time is not typically reported due to the fact that the actual time the incident occurred is often unknown.
Verification Time
T2 – T1
Time between incident being reported and the incident being verified. TMCs can typically assist with verification through use of their CCTV cameras.
Response Time
T4 – T2
Time between the incident being verified and the first responder arriving on scene. Law enforcement may not always be the first party to arrive on scene.
Roadway Clearance Time (RCT)
T5 – T1
Time between the first recordable awareness of the incident by a responsible agency and the first confirmation that all lanes are available for traffic flow.
Incident Clearance Time (ICT)
T6 – T1
Time between the first recordable awareness of the incident by a responsible agency and the time at which the last responder has left the scene.
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