If a vehicle leaves the roadway, ideally, the roadside would be clear of all obstructions and be traversable. However, because there are numerous roadside areas that cannot be practically cleared of all fixed objects or that have sharp declines, roadside safety hardware can be used to reduce the consequences of a departure from the roadway. The goal of roadside safety hardware is met when the hardware contains, redirects, or decelerates the vehicle to a safe stop without causing serious injury to the vehicle’s occupants or other people. General categories for roadside safety hardware are: 1) longitudinal barriers, which include items such as guardrails and cable barriers and are intended to reduce the probability of a vehicle’s striking an object or terrain feature off the roadway that is less forgiving than the barrier; 2) bridge barriers, which function as longitudinal barriers but are specific to bridge design; 3) barrier terminals/crash cushions, which include items like guardrail end terminals that are intended to absorb or divert the energy of a crash into the end of a longitudinal barrier; 4) support structures, such as sign supports, which are designed to break or yield when struck by a vehicle; and 5) work zone devices, which include a variety of items used in a work zone that are temporary in nature. See figure 1 below for a depiction of these types of hardware. DOT’s primary mission is to ensure the safety of the traveling public. The strategic goals of the FHWA, within DOT, are to provide safe, reliable, effective, and sustainable mobility for users of the nation’s highway system. FHWA distributes about $40 billion to the states each year through the federal-aid highway program (generally providing 80 to 90 percent of projects’ costs on designated federal-aid highways) for highway and bridge infrastructure, a portion of which is spent on safety improvements including roadside safety hardware. FHWA issues regulations and guidelines, and can perform direct oversight for projects that use federal funds, including those on the National Highway System (NHS). The NHS consists of approximately 220,000 miles of the nearly 1- million miles of roadways eligible for federal aid. The NHS includes the 47,000-mile Interstate Highway System as well as other roadways, connectors important to U.S. strategic defense policy, and connectors to major intermodal facilities, such as airports or transit hubs. FHWA administers and oversees the federal-aid highway program through FHWA’s division offices located in all 50 states, the District of Columbia and Puerto Rico. As part of FHWA’s risk-based oversight, division offices and state DOTs have “Stewardship and Oversight Agreements” that specify the terms under which states assume oversight responsibility for federally funded projects. Under FHWA’s risk-based stewardship and oversight program, FHWA is responsible for determining projects that have an elevated risk or projects where FHWA involvement can enhance meeting program or project objectives. This involvement may include conducting oversight of the entire project or a specific phase or element of the project. For all projects that FHWA does not categorize as having an elevated risk, responsibility for oversight of design and construction of projects is generally assumed by the states. For each federally funded project, FHWA enters into project agreements with the state in which the state agrees to adhere to all applicable federal laws and regulations. Section 109 of Title 23 of the United States Code directs DOT to work in partnership with the state DOTs to develop standards for the NHS and other roadway systems. To fulfill this responsibility, FHWA works in partnership with AASHTO to advance many of its mission areas. AASHTO is an association representing highway and transportation departments in the 50 states, the District of Columbia, and Puerto Rico. AASHTO serves as a liaison between state departments of transportation and the federal government and develops and maintains design standards for roadways, bridges, and highway materials. FHWA incorporates some AASHTO standards into federal regulation, for example, the Policy on Geometric Design of Highways and Streets (Green Book), which lists design criteria across a range of roadway types, from rural roads to freeways. FHWA has an ex-officio, non-voting role on AASHTO committees. In cooperation, AASHTO and FHWA sponsor research on common transportation issues through the Transportation Research Board’s National Cooperative Highway Research Program (NCHRP), including research on roadside safety hardware. NCHRP studies are funded by the states from federal-aid highway program funds apportioned to them. Roadside safety hardware is developed by manufacturers, states, and universities and can be crash tested to assess its safety performance. The nine U.S. crash-testing labs that are accredited and recognized by FHWA can conduct full-scale crash testing where roadside safety hardware is hit by a vehicle to determine whether it meets AASHTO- accepted standards for roadside safety hardware. Of the nine labs, three labs are independently operated; two are owned by companies that also develop roadside safety hardware; three labs are affiliated with universities; and the final lab is operated by a state department of transportation. Representatives from roadside safety hardware developers, crash test labs, academia, and state and federal transportation departments participate in Task Force 13, a committee whose mission is to develop specifications for new materials and technologies identified for use in highway construction projects. As part of this mission, Task Force 13 develops, recommends, and promotes standards and specifications for roadside safety hardware. The two ways of assessing this performance are lab crash testing and in- service performance evaluations. Crash tests can quantify performance for specific conditions that represent the “worst practical conditions” in terms of the speed and angle of the vehicle hitting the hardware. The performance of hardware is evaluated in terms of risk to the vehicle occupants and structural adequacy of the hardware, among other items. AASHTO currently has two sets of crash-testing standards that it endorses for installing roadside safety hardware: NCHRP Report 350 standards adopted in 1993, which are being phased out, and the Manual for Assessing Safety Hardware (MASH) adopted in 2009. AASHTO developed the MASH standards as an update to NCHRP Report 350, and these standards contain revised criteria for crash tests of roadside safety hardware. Updates in MASH include: increases in the size and weight of several test vehicles to better match the current vehicle fleet, changes to the number of tests and impact conditions, and more objective evaluation criteria. AASHTO has also sponsored research on how to assess the performance of roadside safety hardware once it has been installed, an assessment that is referred to as in-service performance evaluation (ISPE). In 2003, NCHRP Report 490: In-Service Performance of Traffic Barriers, published findings of research and suggested practical procedures for conducting ISPEs. In-service performance evaluations are a way of assessing roadside safety hardware’s performance in “real- world” scenarios not captured in a crash-test setting. For example, performance may be affected by installation factors, such as slope and grade of roadway and soil type, and maintenance conditions, including whether the hardware has degraded over time from weather or accidents, none of which are captured in crash-testing. FHWA oversees and promotes the installation of crash-tested roadside safety hardware through guidance and policy directives to the states and by issuing letters to roadside safety hardware developers that submit crash-test results for review by FHWA. We found that states generally require crash testing; however, some inconsistencies across state policies and practices exist, and a movement to adopt the improved MASH standards has been slow. In 2016, FHWA and AASHTO released a new Joint Implementation Plan stating that states should transition to installing only MASH-standard-tested roadside safety hardware in phases by 2019. However, some concerns have been raised, and FHWA has not developed a plan to track progress of the states and industry in meeting the new dates. FHWA has contracted for a full examination of its roadside safety hardware oversight processes and expects a report with recommendations for potential changes to these processes in the summer of 2016. In line with its overall safety mission as well as that of DOT, FHWA encourages states to install appropriately crash-tested roadside safety hardware. By law, FHWA is required to ensure that highway projects designed and constructed with federal funds are safe. FHWA’s Office of Safety’s specific mission includes advancing the use of scientific methods and data-driven decisions. Also, according to FHWA’s Office of Safety website, roadway departure is one of its focus areas. FHWA has issued policy that roadside safety hardware should demonstrate acceptable crashworthy performance in order to be used on the NHS and receive federal-aid reimbursement. To encourage this outcome, FHWA issues guidance and policy directives to the states and industry. For example, in 2015 FHWA issued a memo that encouraged state agencies to upgrade their existing installations of guardrail end terminals that had been tested to standards issued prior to the NCHRP 350 standards, which were adopted in 1993. Congress directs DOT to work in partnership with the state DOTs to develop standards for the NHS and other systems. FHWA works in cooperation with AASHTO to promote state adherence to crash-testing standards through joint implementation plans. These plans are voted on and must be approved by a majority of AASHTO’s member states. FHWA and AASHTO issued joint implementation plans in 2009 and 2016 that provided guidance for states to follow in transitioning to updated crash test standards. In addition to providing guidance to states, FHWA also issues federal-aid reimbursement eligibility letters to roadside safety hardware developers that submit their product information, crash test results and other supporting documentation for review.