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Suggested Citation:"Chapter One - Introduction." National Academies of Sciences, Engineering, and Medicine. 2008. Light Rail Vehicle Collisions with Vehicles at Signalized Intersections. Washington, DC: The National Academies Press. doi: 10.17226/14215.
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Suggested Citation:"Chapter One - Introduction." National Academies of Sciences, Engineering, and Medicine. 2008. Light Rail Vehicle Collisions with Vehicles at Signalized Intersections. Washington, DC: The National Academies Press. doi: 10.17226/14215.
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Suggested Citation:"Chapter One - Introduction." National Academies of Sciences, Engineering, and Medicine. 2008. Light Rail Vehicle Collisions with Vehicles at Signalized Intersections. Washington, DC: The National Academies Press. doi: 10.17226/14215.
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3At start-up, new light rail transit (LRT) operating systems typ- ically experience undesirable frequencies of light rail vehicle (LRV)–motor vehicle collisions, particularly where motor vehicles cross LRT tracks located in or adjacent to highway intersections that are controlled by conventional traffic signals. Over time, as agencies have gained experience with LRT oper- ations, they have addressed the problems by making changes to pavement markings, signs, signals, street geometrics, oper- ating procedures, and training programs. This report is a syn- thesis of today’s state of the practice with regard to mitigating collisions between LRVs and motor vehicles at signalized intersections. This synthesis will help transit agencies to better understand and to learn from the experiences of other agencies facing similar challenges. OBJECTIVE The objective of this study was to report on the mitigation methods tested and used by transit agencies to reduce collisions between LRVs and motor vehicles where LRT runs through or adjacent to highway intersections controlled by conventional traffic signals, with a particular focus on collisions occurring between LRVs and vehicles making left turns at these inter- sections. This synthesis includes success stories and specific actions taken to achieve positive results, as well as examples of unsuccessful actions. The issues addressed include a range of LRT operations and environments (median-running, side- running, contra-flow, and mixed-use LRT alignments), urban and suburban settings, and a variety of U.S. geographic regions. TECHNICAL APPROACH The technical approach for this synthesis project included a review of recent relevant literature, as well as a survey of selected light rail systems. Regarding the relevant literature, two documents form the basis for improving light rail safety within city streets and in semi-exclusive rights-of-way: TCRP Report 17: Integration of Light Rail Transit into City Streets (1) and TCRP Report 69: Light Rail Service: Pedestrian and Vehicular Safety (2). TCRP Report 17, published in 1996, was a comprehensive study of 10 LRT systems across North Amer- ica, and included a literature review, structured interviews of the transit agencies, accident analyses, and recommendations for improving safety of LRT operations within city streets. It addresses the safety and operating experience of LRT systems operating on shared rights-of-way at speeds generally less than 35 mph. TCRP Report 69, published in 2001, documents and presents the results of a comprehensive study to improve the safety of LRT in semi-exclusive rights-of-way where LRVs operate at speeds greater than 35 mph. The analysis presented in this report is based on interviews with LRT agency officials, field observations, and analysis of accident records and acci- dent rates at 11 LRT systems in the United States and Canada. The report presents guidelines that may be considered in plan- ning and designing new LRT systems or in retrofitting and extending existing LRT systems. The research for TCRP Report 17 and TCRP Report 69 was conducted more than 7 and 12 years ago, respectively. Since that time, many of the systems interviewed for these studies have expanded, and other new systems have begun service or are about to begin service. Thus, the research conducted for this synthesis report identified the current state of the practice by focusing primarily on studies that have been conducted since these earlier studies, while using the results from these earlier studies as a baseline. Two additional and particularly relevant sources referenced throughout this synthesis include a research paper, Median Light Rail Crossings: Accident Causation and Counter- measures (3) and the METRORail Traffic Safety Assessment (4), both of which offer insight into the issues surrounding LRV–motor vehicle collisions at signalized intersections, as well as a variety of countermeasures for mitigating these types of collisions. To supplement the recent relevant literature, a survey of LRT systems was undertaken. The surveys were administered by means of the telephone in the form of structured interviews. Structured telephone interviews were chosen over a written survey for a number of reasons. First, considering the topic, it was important to obtain detailed information about particular problematic intersections, collision circumstances, measures taken to mitigate the collisions, and effectiveness of the countermeasures. Structured telephone interviews allowed the researchers to probe those being surveyed for more com- plete responses, resulting in more detailed and comprehensive information. Second, although there are more than 30 agencies that operate rail systems in semi-exclusive or mixed traffic environments, only approximately 20 are LRT systems (as opposed to trolley or street car systems), and of these systems, only about 15 were appropriate to include in this study (one system had no operating history, with an opening day of CHAPTER ONE INTRODUCTION

November 2007; several others operated primarily in exclu- sive rights-of-way; and some had only gated crossings at sig- nalized intersections). With the population for the survey being only about 15 systems, the researchers and panel members agreed that structured telephone interviews with a carefully selected sample of these systems would be the best approach for this synthesis. Nine LRT systems were selected and contacted for partici- pation in the survey. These nine agencies were selected based on three criteria: collision history/frequency, operating envi- ronment, and system age. They represented a range of collision experience, including systems with relatively low collision frequencies (i.e., those that are controlling collisions), as well as those that initially had problems, but have shown reductions in collision rates over the years. Their operating environments included a range of alignments (median-running, side-running, mixed-use, and contra-flow), geographic locations, and urban settings (central business district, suburban). Finally, the age of the systems selected ranged from one that has been operational for more than 20 years to one that has been operational for only 4 years. Of the nine systems contacted, the following seven systems participated in the telephone interviews: • Tri-County Metropolitan Transportation District of Oregon (TriMet)—Portland, Oregon; • Denver Regional Transportation District (RTD); • Metropolitan Transit Authority of Harris County (METRO)—Houston, Texas; • Los Angeles County Metropolitan Transportation Authority (LACMTA); • New Jersey Transit—Hudson–Bergen Light Rail; • Sacramento Regional Transit District (RT); and • Dallas Area Rapid Transit (DART). Some of these agencies were also interviewed for the develop- ment of TCRP Reports 17 and 69. Table 1 shows the overlap in the LRT systems that were included in TCRP Report 17, TCRP Report 69, and this synthesis project. The primary objective of the structured interviews for this synthesis was to identify the current state of the practice at each agency for mitigating LRV–motor vehicle collisions at signal- ized intersections. For the older systems, the interviews served to obtain an update on what improvements had been imple- mented over the past decade since the previous TCRP research studies were conducted, including experiences with system expansions. For the newer systems, the interviews served to identify start-up experiences. 4 Before administering the telephone survey, agency repre- sentatives were contacted through e-mail to provide back- ground to the synthesis project, to invite them to participate in the research, and to schedule an interview time. The interviews generally lasted between 30 min and 1 h. Five main topics were covered during the interviews: • History of LRT operations (e.g., when LRT operations began, when expansions occurred). • LRT operating environment (e.g., LRT alignments; number of signalized intersections through which the LRT operates; number of intersections with crossing gates, signal operations, existing traffic control). • LRT–motor vehicle collision history (frequency and type of collisions, common causal factors). • Mitigating collisions between LRVs and motor vehicles at signalized intersections (e.g., countermeasures tested or implemented, effectiveness). • Recommendations for other agencies with start-up sys- tems or those experiencing problems with collisions at signalized intersections. During the interviews, the interviewees’ responses to ques- tions were recorded and detailed notes were taken. Fol- lowing the interviews, each person interviewed was sent a summary of the interview that they reviewed for accuracy and completeness. SYNTHESIS ORGANIZATION This synthesis report is organized into five chapters. Follow- ing this introductory chapter is chapter two that includes discussions of the most common types of collisions between LRVs and motor vehicles at signalized intersections and the contributing factors to LRV–motor vehicle collisions at signalized intersections. Chapter three then provides details regarding a large array of countermeasures tested and/or used by transit agencies to mitigate collisions between LRVs and motor vehicles at signalized intersections. Countermeasures include physical barriers, traffic signal phasing, signs, LRT and traffic signal displays, pavement markings and/or treat- ments, public outreach and education, and enforcement. Chapter four contains case studies that present the most recent challenges by select transit agencies regarding LRV–motor vehicle collisions at signalized intersections, including suc- cessful countermeasures where applicable. Finally, chapter five presents a summary of the conclusions drawn from the research effort.

5TABLE 1 LRT SYSTEMS REVIEWED IN TCRP RESEARCH Agency/LRT System Began Operation TCRP Report 17 (1996) TCRP Report 69 (2000) TCRP Synthesis 79 (2008) Massachusetts Bay Transportation Authority (Boston) 1889/1897 San Francisco Municipal Transportation Authority/Muni 1897/1981 Edmonton Transit System/LRT 1978 San Diego Trolley 1981 Calgary Transit/C-Train 1981 Niagara Frontier Transportation Authority (Buffalo)/Metro Rail 1984 Tri-County Metropolitan Transportation District of Oregon (TriMet)—Portland 1986 Santa Clara Valley Transportation Authority 1987 Sacramento Regional Transit District (RT) 1987 Los Angeles County Metropolitan Transportation Authority (LACMTA) 1990 MTA (Baltimore)/Light Rail 1992 Metro (St. Louis)/MetroLink 1993 Denver Regional Transportation District (RTD) 1994 Dallas Area Rapid Transit (DART) 1996 (Not operational at the time) New Jersey Transit—Hudson– Bergen Light Rail 2000 (Not operational at the time) Metropolitan Transit Authority of Harris County (METRO)— Houston 2004 (Not operational at the time) (Not operational at the time) Note: Boldface type indicates transit agencies that were interviewed for this synthesis project.

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TRB's Transit Cooperative Research Program (TCRP) Synthesis 79: Light Rail Vehicle Collisions with Vehicles at Signalized Intersections explores mitigation methods tested and used by transit agencies to reduce collisions between light rail vehicles (LRVs) and motor vehicles where light rail transit (LRT) runs through or adjacent to highway intersections controlled by conventional traffic signals.

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