Measuring and Communicating the Effects of Traffic Incident Management Improvements (2004)

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1 1 INTRODUCTION 1.1 Background to the Problem State Departments of Transportation (DOTs) are actively engaged in traffic incident management, and this activity is expanding. It is widely believed by the profession that traffic incident management provides substantial user benefits in terms of both decreased delay and improved safety (due to removing conditions that lead to secondary crashes). However, the profession has not been able to articulate and demonstrate the magnitude of these benefits (absolute and relative to other programs, especially capital ones) to users and decision makers. The inability to communicate the benefits is caused by three basic problems. First, little agreement has been reached on the data, performance measures, and analysis methods to document traffic incident management effects. The effects of incidents are often difficult to assess because they are confounded with other sources of congestion (e.g., recurring bottlenecks and weather). In contrast, other program areas with which traffic incident management must compete for fund allocation (e.g., pavement maintenance, bridges, and capital construction) have long- standing histories of providing condition and performance information, as well as expected benefits to upper DOT management and lawmakers. Second, actual measurement of benefits is not taking place. Although some DOTs have started the process, data and methodological problems have yet to be resolved, and little consistency in these items exists between areas. Third, once technical hurdles are overcome, the marketing or “packaging” of traffic incident management programs has usually been ineffective, even though several factors reinforce the significance of traffic incident management in addressing congestion: • Traffic incident management represents the only short-term means of producing measurable freeway service (and safety) improvements. Traffic incident management programs can be implemented quickly and cheaply compared with highway expansion (i.e., construction) projects. • Traffic incident management activities highlight the importance of nonrecurring congestion and its effect on both total delay and reliability. Reliability is a concept that is growing in importance to transportation agencies. The most workable definition of “reliability” is how travel conditions vary over time. Because incidents are the dominant source of variable traffic conditions in urban areas, reliability – or lack thereof – is directly linked to them. • Traffic incident management ties in with the increased focus of DOTs on overall emergency transportation operations and security. Effective traffic incident management programs coordinate the activities of a variety of agencies, including transportation, police, fire, emergency medical, and specialized response units. These agencies must be involved in coordinating response to natural and non-natural disasters. By involving these agencies in routine traffic incident management activities, institutional barriers to cooperation are overcome.

2 1.2 Purpose of this Digest The purpose of this digest is to develop the best short-run strategy using available data to document and communicate the benefits of traffic incident management. Specifically, three issues are addressed: 1. Report the results of the workshop convened in Seattle, Washington, December 2-3, 2003. The structure of this report – and much of the information presented – can be traced to the discussions at the workshop. 2. Compile current practices in (a) developing traffic incident management benefits and (b) communicating the benefits to upper DOT management, decision makers, and the public. 3. Recommend a framework for moving forward. This report cannot be expected to reconcile many of the institutional difficulties that confound the interagency cooperation needed for sound traffic incident management. The content was purposely prepared from the perspective of transportation agencies, primarily state DOTs, yet many more entities must be involved. In particular, the viewpoints of personnel from public safety, law enforcement, fire, emergency medical services, hazardous material teams, and private towing operators must all be considered. Such coordination is beyond the scope of the current effort, but can be taken up in several of the forums and other recommendations referenced herein. Providing the perspective of transportation agencies is an important first step in this process – it provides a way to communicate what is important and what is needed in an ideal environment. However, transportation agencies must recognize that it may be necessary to deviate from the ideal to reflect the viewpoints of other agencies involved in traffic incident management. 1.3 Project Workshop The primary inputs for this report came from discussions at the December 2-3, 2003, workshop. The workshop had two parts: (1) presentations on the current state of the practice and (2) discussions of the issues needing resolution. The initial presentations given were the following: • Purpose of Workshop (Doug MacDonald) • State of Practice Review • Practitioner Experience #1: Washington • Practitioner Experience #2: California • Practitioner Experience #3: Maryland/CHART • Practitioner Experience #4: FHWA and National Perspectives Appendix A contains the presentations made by several of the participants. Topics of discussion following the presentations included the following: • Modeling and Measurement Methods for Developing Metrics o What definition of an incident and what incident timeline (e.g., detection, verification, on-scene arrival, clearance, departure, etc.) should be used? o What is the right mix of modeling and measurement?

3 o What is required to quantify the various sources of congestion? o Should standard procedures be developed to ensure consistent reporting? • Impacts of Various Incident Management Strategies o How should they be measured? o Can national standards or benchmarks for incident management performance (e.g., delay reduction, response times, etc.) be established and are they even desirable from the profession’s perspective? o Do the incident management strategies cause a measurable change in the selected performance metrics? • Ways to Communicate the Benefits of Incident Management o How should the media be used? o How should education campaigns for the public and decision makers be used? • Metrics to Use o What resonates with the profession, decision makers, and the public? o Are there performance measures for output, outcome, or both? o Are there metrics for total/average congestion and reliability? o Are there multiple metrics (e.g., local versus national)? o Are there standard definitions for incident, other congestion sources, recurring congestion, nonrecurring congestion, delay, and free flow? As a result of the workshop, an annotated outline was developed and revised based on feedback from the participants. The annotated outline served as the basis for this digest.