Roadside Hardware Replacement Analysis: User Guide (2021)

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1 1 BACKGROUND On December 21, 2015, the Federal Highway Administration (FHWA) and the American Association of State Highway and Transportation Officials (AASHTO) jointly agreed on a plan to implement the new crash test and evaluation procedures in the AASHTO Manual for Assessing Roadside Hardware (MASH) (1). In subsequent years the FHWA and AASHTO have issued several memoranda providing clarification about the dates, roles and responsibilities for accomplishing the transition (2). While the implementation plan provides specific dates for when new hardware installations should comply with the MASH crash testing requirements, the plan urges states and other highway agencies to “upgrade existing highway safety hardware to comply with the 20151 edition of MASH either when it becomes damaged beyond repair, or when an individual agency’s policies require an upgrade to the safety hardware” (1). While the implementation plan encourages agencies to upgrade existing safety hardware to MASH 2016 it does not provide any specific guidance on how to establish priorities or policy on how such upgrading should occur. This user guide presents a method that highway agencies can use to establish these priorities for individual projects or as policy guidelines. The AASHO-FHWA agreement classifies roadside hardware projects into three categories: • Roadside hardware used in new construction is subject to specific dates for each type of hardware. Construction projects let after the appropriate date for each type hardware must satisfy the MASH 2016 criteria. The 2018 AASHTO “Green Book” defines new construction as projects “that construct roads on new alignments where no existing roadway is present” (3). Roadside hardware used in reconstruction projects are also considered “new” hardware since reconstruction projects are “those that utilize an existing roadway alignment… but involve a change in the basic roadway type” (3). • Existing hardware is already installed in the field and not part of a new construction or reconstruction project. For example, roadside hardware on re-surfacing projects may still be in serviceable condition but not evaluated according to MASH. Highway agencies are encouraged to upgrade existing non-MASH hardware but there is no specified process for prioritizing that work. • Highway agencies are encouraged to replace existing non-MASH hardware that is “damaged beyond repair” with MASH evaluated hardware (2). There is no specific definition of “damaged beyond repair” and no specific policy for prioritizing this work either. This guide deals with the second two categories of hardware – existing still serviceable hardware and damaged hardware. Today, the majority of any highway agency’s roadside hardware has not been evaluated according to MASH but is probably in reasonably good repair and functional and would likely remain functional for a considerable period of time. For example, a highway agency may have installed a 27-inch tall w-beam guardrail on a particular pavement overlay project just prior to the 2015 FHWA memorandum. The guardrail is relatively new and in good repair today but 27- inch w-beam guardrail is not MASH compliant. Crash tests have shown that 31-inch tall w-beam guardrail passes the MASH criteria (4). Should the agency immediately replace the recently installed 1 While the implementation plan refers to the 2015 edition of MASH, the 2nd Edition did not actually appear until 2016.

2 27-inch guardrail with 31-inch guardrail? Waiting until the 27-inch guardrail is “damaged beyond repair” may mean the guardrail stays in service for decades (1). Is that acceptable? The recently installed non-MASH 27-inch guardrail probably also has Report 350 guardrail terminals and guardrail-bridge rail transitions that are also in good repair since they were only recently installed. When should they be upgraded to MASH 2016? Is the priority for upgrading the terminals the same as upgrading the w-beam guardrail? These are the types of questions that highway agencies face in developing a “process to replace existing highway safety hardware” (1). Establishing priorities for upgrading roadside hardware is not a new activity in roadside design. A similar situation occurred when NCHRP Report 350 appeared in the 1990s (5). After NCHRP Report 350 was published, the FHWA incorporated it as one of the guides and references for design standards for highways in 23 CFR Part 625 (6). In 1998 AASHTO and the FHWA negotiated an implementation agreement with specific dates for each type of roadside hardware much like the MASH implementation agreement (7). The 1998 AASHTO-FHWA agreement also categorized hardware into three groups: hardware used in new construction, hardware used on 3R project, and systemwide replacements. There were specific dates for upgrading each type of hardware for each of the three categories. For example, systemwide replacement was not required for most hardware meaning pre-Report 350 hardware that was in place in the field could remain until the roadway was reconstructed or a 3R project was programed. The exception to this were Category III work zone devices which had to be replaced systemwide by 1 October 2002. What was meant by “3R” projects was explained in note 3 of the memo. New construction was defined as “a new installation of a feature … where none exists” (7). Upgrading the hardware for an existing feature that had to be “moved, reconstructed, or extended” in a reconstruction project was recommended although agencies, as in the MASH implementation agreement, were encouraged to develop policies to address these situations (7). The need, therefore, to establish priorities for upgrading existing hardware to hardware that meets newer crash testing guidelines occurs periodically in roadside safety and a method for more systematically implementing priorities for upgrading is a recurring need. In the past, policies have been developed primarily using engineering judgement rather than a systematic assessment of the effectiveness and economics of upgrading existing hardware. The purpose of this user manual is to present a method that the highway agencies can use to prioritize upgrading existing roadside hardware to new crash test requirements. The roadside hardware covered by MASH 2016 includes guardrails, median barriers, bridge railings, transitions, guardrail terminals, crash cushions, breakaway sign supports, luminaire supports and work zone hardware. Upgrading all of these types of devices to MASH 2016 is a large undertaking that will take many years and significant funding to accomplish. Since everything cannot be accomplished at once, user agencies need a means for developing hardware upgrade policies that implement MASH 2016 hardware in a systematic, staged, and prioritized manner. This manual presents a systematic data- driven method that user agencies can use to establish upgrading priorities. Implicit in this discussion is the recognition that just because crash test procedures and evaluation criteria change does not mean that hardware developed using earlier criteria suddenly becomes unsafe. The process of improving roadside safety hardware is an incremental process where each generation of hardware is thought to be slightly more effective than the previous generation. Prioritizing upgrading policies involves assessing the incremental reduction in the risk of fatal and serious injury expected from upgrading roadside hardware and balancing that risk reduction with the highway agency costs of upgrading the hardware such that funds are expended to maximize overall