Reliability of Safety Management Methods: Network Screening

2016Thompson, StuartPDFTech ReportFHWA-SA-16-037DTFH61-10-D-00022-T-13005Safety managementReliabilityNetwork analysis (Planning)Highway safetyDecision makingUnited StatesUnited States. Federal Highway Administration. Office of SafetySrinivasan, RaghavanGross, Frank B.Lan, BoBahar, Geni BrafmanUnited States. Federal Highway Administration. Office of SafetyVHB/Vanasse Hangen Brustlin, Inc.Thompson, StuartFederal Highway AdministrationHigh quality data and reliable analytical methods are the foundation of data-driven decision-making. The Reliability of Safety Management Methods series includes five information guides that identify opportunities to employ more reliable methods to support decisions throughout the roadway safety management process. Four of the guides focus on specific components of the roadway safety management process: network screening, diagnosis, countermeasure selection, and safety effectiveness evaluation. The fifth guide focuses on the systemic approach to safety management, which describes a complimentary approach to the methods described in the network screening, diagnosis, and countermeasure selection guides. The purpose of the Reliability of Safety Management Methods series is to demonstrate the value of more reliable methods in these activities, and demonstrate limitations of traditional (less reliable) methods. The Reliability of Safety Management Methods: Network Screening guide describes various methods and the latest tools to support network screening. The target audience includes data analysts, program managers, and project managers involved in projects that impact highway safety. The objectives of this guide are to 1) raise awareness of more reliable methods, and 2) demonstrate through examples the value of more reliable methods in network screening. This guide compares more reliable crash-based performance measures to traditional measures which are more susceptible to bias and may result in less reliable results and less effective decisions. Readers will understand the value of and be prepared to select more reliable performance measures in network screening. This guide includes five sections and an appendix. The first section introduces the roadway safety management process and network screening. The second section provides an overview of various performance measures for conducting network screening, including a discussion of the associated strengths and limitations. The strengths and limitations focus on the ability (and inability) of the measures to account for issues in network screening that can lead to less reliable results. The third section demonstrates the value of applying more reliable performance measures in network screening. Empirical examples highlight the shortcomings of less reliable measures, which lead to less reliable results and conclusions. The next section summarizes the data requirements to employ the various measures. The final section describes available tools and resources to support network screening. The appendix presents further details on the empirical examples used to demonstrate the value of applying more reliable performance measures in network screening.84