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Suggested Citation:"I. Introduction ." National Academies of Sciences, Engineering, and Medicine. 2010. Volume I: Evaluation of Existing Roadside Safety Hardware Using Updated Criteria—Technical Report. Washington, DC: The National Academies Press. doi: 10.17226/22938.
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Suggested Citation:"I. Introduction ." National Academies of Sciences, Engineering, and Medicine. 2010. Volume I: Evaluation of Existing Roadside Safety Hardware Using Updated Criteria—Technical Report. Washington, DC: The National Academies Press. doi: 10.17226/22938.
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1 I. INTRODUCTION RESEARCH PROBLEM STATEMENT National Cooperative Highway Research Program (NCHRP) Report 350 “Recommended Procedures for the Safety Performance Evaluation of Highway Features” contains guidelines for evaluating the safety performance of roadside features, such as longitudinal barriers, terminals, crash cushions, and breakaway structures.(1) This document was published in 1993 and was formally adopted as the national standard by the Federal Highway Administration (FHWA) later that year with an implementation date for late 1998. In 1998, the American Association of State Highway and Transportation Officials (AASHTO) and Federal Highway Administration (FHWA) agreed that most types of safety features installed along the National Highway System (NHS) must meet NCHRP Report 350 safety-performance evaluation criteria. An update to NCHRP Report 350 was developed under NCHRP Project 22-14(02), “Improvement of Procedures for the Safety-Performance Evaluation of Roadside Features.” This document, Manual for Assessing Safety Hardware (MASH) published by AASHTO, contains revised criteria for safety-performance evaluation of virtually all roadside safety features.(2) For example, MASH recommends testing with heavier light truck vehicles to better represent the current fleet of vehicles in the pickup/van/sport-utility vehicle class. Further, MASH increases the impact angle for most small car crash tests to the same angle as the light truck test conditions. These changes place greater safety-performance demands on many of the current roadside safety features. State DOTs make considerable use of non-proprietary systems (such as weak-post W-beam, low-tension three-strand cable barrier, and box-beam). Although some barrier testing was performed during the development of the updated criteria, many barrier systems and other roadside safety features had yet to be evaluated under the proposed guidelines. Therefore, evaluation of the remaining widely used roadside safety features using the safety-performance evaluation guidelines included in the update to NCHRP Report 350 (MASH) was needed. RESEARCH OBJECTIVE The objective of this project was to evaluate the safety performance of widely used non- proprietary roadside safety features by using MASH. Features recommended for evaluation included longitudinal barriers (excluding bridge railings); terminals and crash cushions; transitions; and breakaway supports. Evaluation methods included, but were not limited to, engineering assessment, simulation, full-scale crash testing, pendulum testing, and component testing. Where practical, cost-effective modifications to systems that do not meet the new criteria were recommended for future evaluation.

2 Accomplishment of the project objective required the following tasks. Task Description 1 Identify Non-Proprietary Roadside-Safety Features & Frequency of Use by State DOTs 2 Review All Applicable Information & Create Matrix 3 Prepare & Submit Interim Report 4 Meet with Project Panel 5 Execute Work Plan 6 Submit Final Report This Final Report documents the performance of Tasks 1 through 6.

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 Volume I: Evaluation of Existing Roadside Safety Hardware Using Updated Criteria—Technical Report
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TRB’s National Cooperative Highway Research Program (NCHRP) Web-Only Document 157: Volume I: Evaluation of Existing Roadside Safety Hardware Using Updated Criteria—Technical Report explores the process that was followed in developing NCHRP Research Results Digest (RRD) 349: Evaluation of Existing Roadside Safety Hardware Using Manual for Assessing Safety Hardware (MASH) Criteria.

NCHRP RRD 349 explores the safety performance of widely used non-proprietary roadside safety features by using MASH. Examples of features evaluated include longitudinal barriers (excluding bridge railings), terminals and crash cushions, transitions, and breakaway supports.

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