The commercial motor-carrier industry is a vital part of the U.S. economy. As of December 2015, FMCSA estimated that there were 551,150 active carriers and approximately 6 million commercial drivers operating in the United States. The domestic commercial motor-carrier industry includes a range of businesses, including private and for-hire freight transportation, passenger carriers, and specialized transporters of hazardous materials. These carriers also range from small carriers with only one vehicle that is owned and operated by a single individual, to large corporations that own tens of thousands of vehicles. FMCSA is responsible for overseeing this large and diverse industry. In fiscal year 2016, FMCSA had a budget of approximately $580 million and more than 1,000 staff members located at its Washington, D.C., headquarters, four regional service centers, and 52 division offices. FMCSA establishes regulations for all interstate motor carriers in addition to intrastate hazardous-material carriers. FMCSA regulations set requirements, among others, for the motor vehicle parts and accessories—“equipment”—required for safe operation. For example, FMCSA’s regulations require vehicles to have certain lights, tire tread depth, and parking brakes. Other FMCSA regulations require carriers and their drivers to systematically inspect, repair, and maintain their vehicles. Before beginning their trip each day, commercial motor vehicle drivers must conduct a pre-trip inspection to ensure that their vehicles are in safe operating condition, meaning that they meet the maintenance requirements set forth in FMCSA regulations. Commercial driver’s license tests require drivers to show they can inspect the engine components, brakes, steering, and other equipment. If during the pre- trip inspection the driver identifies an equipment problem that would affect the safe operation of the vehicle, the driver must ensure it is repaired before starting a trip. At the end of each day, drivers are also required to prepare a daily vehicle inspection report (DVIR), which lists any equipment problems identified that day. Drivers submit the DVIRs to their carrier, which must repair any issues before sending the vehicle on another trip. Regulations also require carriers to conduct comprehensive inspections of their vehicles annually. FMCSA regulations set the minimum requirements for commercial motor vehicles, but individual carriers may have their own additional requirements regarding when and how their vehicles are inspected and repaired. To oversee the safety performance of the commercial motor carrier industry, FMCSA and state agencies such as highway patrols perform roadside inspections of carriers’ vehicles. These roadside inspections are intended to provide a snapshot of commercial motor vehicles’ maintenance and assess the effectiveness of carriers’ maintenance programs. Specially trained and certified personnel serve as inspectors and select commercial motor vehicles for inspection as they pass through a roadside inspection location such as a weigh station. The inspector compares the vehicle’s condition to requirements listed in FMCSA’s regulations and issues a violation if there are discrepancies. If the inspector determines that the violation could likely cause an accident or breakdown (for example, if more than 20 percent of the vehicle’s brakes are defective) the vehicle is placed out-of-service until it is repaired. FMCSA regulations prohibit carriers from operating a vehicle that has been deemed “out-of-service” by an inspector. The Commercial Vehicle Safety Alliance, an association comprised of federal and state commercial- vehicle safety officials and private industry representatives, provides guidance on the criteria that render a vehicle out-of-service. Even if violations are found, if the vehicle is not deemed out-of-service, the driver is allowed to continue driving, though FMCSA regulations require carriers to repair all violations before the vehicle starts another trip. In addition, within 15 days of receiving the violation, carriers must certify they have made repairs by signing a copy of the inspection report and sending it to the state department of transportation. See figure 1 for four examples of vehicle maintenance violations—the top two depict improper load securement and the bottom two depict missing wheel fasteners. In both rows, the violation on the right is an out-of-service violation. FMCSA uses the data on violations submitted by inspectors to rank carriers’ relative safety performance in seven categories and assign carriers to a percentile in each. One of the categories, the vehicle maintenance Behavior Analysis and Safety Improvement Category (BASIC), takes into account violations related to failing to properly maintain a commercial motor vehicle and failing to secure loads. FMCSA uses these BASIC percentiles to identify and target “high-risk” carriers for interventions, such as warning letters and on-site investigations. In 2014, we reported on the effectiveness of SMS and found that FMCSA faces challenges in reliably assessing safety risks for the majority of carriers. We recommended that FMCSA revise the SMS methodology to better account for limitations in drawing comparisons of safety performance information across carriers. As of November 2016, FMCSA has not implemented our recommendation. The FAST Act directed FMCSA to address the issues raised in our report and required that FMCSA remove the BASIC percentiles from public view on its website until then, which it has done. One of the challenges in assessing the safety impact of a potential system for self-reporting equipment problems is its hypothetical nature. As described above, based on one of the provisions in the FAST Act and discussions with FMCSA and stakeholders, we made a number of assumptions about such a system. We assumed that a self-reporting system would: apply only to problems identified during a driver’s day, that is between the pre-trip inspection and the end of the day when the driver vehicle inspection report is completed; not apply to equipment problems that would result in out-of-service require drivers to report equipment problems and repairs through a telephone hotline or Internet website or other electronic platform; require repairs to be made before the beginning of the next day on duty (e.g., within a day of when the problem was reported, if the driver ended his trip that evening and planned another trip the following day); still result in a carrier receiving a violation for the equipment problem if pulled over for a roadside inspection, but once a self-reported equipment problem was repaired within the requisite time frame and FMCSA was so notified, FMCSA would exclude the violation from the carrier’s relative safety ranking (i.e., BASIC percentile for vehicle maintenance); and not prompt FMCSA to take action if a carrier or driver self-reported an equipment problem, but never received a violation for that equipment problem. Figure 2 below illustrates some of the key differences between the current process for identifying and repairing equipment problems and the process under a potential self-reporting system with the features assumed above. The Office of Management and (OMB) and the Department of Transportation (DOT) provide guidance on estimating a program’s societal impact, such as its health and safety benefits, through a benefit- cost analysis. For example, DOT’s Economic Analysis Primer states that a benefit-cost analysis requires the identification of a base case—usually the status quo—so that the benefits and costs associated with implementing the new program can be compared against this base. For a new program designed to affect safety, identifying the base case and the potential benefits of the new program generally requires data on past events related to the type of bad outcomes (i.e., injuries and deaths) that the new program is expected to reduce. Even after putting some parameters on a hypothetical system for self- reporting equipment problems (i.e., our assumptions), estimating its overall safety impact is challenging for two key reasons: 1. We did not identify any conclusive data on the “base case” or status quo for a self-reporting system—that is, data on how non-out-of- service equipment problems are related to safety outcomes. FMCSA and the National Highway Traffic Safety Administration estimated that equipment problems such as braking capacity, tire or wheel failure, or shifting cargo were the critical reason for a crash in about 10 percent of the crashes for which a critical reason was assigned to a truck, as reported in the Large Truck Crash Causation Study. However, this study was issued 11 years ago and did not separately present data for or otherwise discuss the extent to which non-out-of-service equipment problems were related to crashes. Further, our review of literature and interviews with FMCSA did not identify any additional data. Consequently, there is no baseline against which to evaluate the extent to which safety may be improved with the implementation of such a system. 2. Even if such data were available, we determined that an assessment of potential safety impacts would also require information on the extent to which a self-reporting system would change the frequency or speed with which drivers make equipment repairs. This would require information on both the frequency and speed with which carriers currently make repairs, and how a self-reporting system would change that behavior. Both, however, are unknown and difficult to determine because they would require predicting behavior under hypothetical conditions. For a self-reporting system to impact safety, carriers and drivers would have to use it, but the majority of carriers and drivers we interviewed said their use of a potential self-reporting system would depend on various factors. The most frequently cited factor was ease of use. For example, some said they preferred a telephone hotline to a web-based application; others said the opposite. One carrier and one driver said they would use a self-reporting system if they thought they were traveling a route where an inspection was likely. Another carrier said it might use a self-reporting system if it afforded them increased flexibility to wait to repair low risk equipment problems at a less expensive repair facility, such as the carrier’s own maintenance facility. Representatives from five of six industry and safety associations we interviewed said they would be unlikely to support a self-reporting system as outlined above. Industry and safety representatives cited reasons such as an administrative burden for drivers and carriers, and potentially negative safety impacts, as described below.