FMCSA was established within the Department of Transportation (DOT) in January 2000, and is tasked with promoting safe commercial motor vehicle operations and reducing large truck and bus crashes, injuries, and fatalities. It seeks to achieve this reduction through regulation, enforcement, and partnerships with stakeholders, among other activities, and with full accountability to the public through transparency, results- oriented performance measuring, and managing for results. Since fiscal year 2010, FMCSA’s total budget authority to conduct these activities has remained relatively stable, increasing about 6.5 percent from fiscal year 2010 through fiscal year 2016 (see table 1). Funding for implementing and applying interventions is included in both the Motor Carrier Safety Operations and Programs and Safety Grants budget authorities. The vast majority of FMCSA’s staff are located in field offices, including divisions and service centers. Field staff are primarily responsible for implementing FMCSA’s compliance and enforcement activities, including investigations. Federal Safety Investigators represent the majority of FMCSA’s compliance and enforcement program staff (see table 2). In addition, FMCSA partners with state agencies to perform some intervention activities, such as conducting carrier investigations; however, FMCSA is responsible for ensuring that commercial motor carriers under its authority comply with federal safety regulations. FMCSA’s Office of Enforcement is the primary office responsible for developing policy for FMCSA’s compliance and enforcement program, and overseeing the implementation of intervention activities. The CSA program is intended to improve the effectiveness of FMCSA’s compliance and enforcement programs, while more efficiently using its resources to reach carriers that pose the highest safety risk. The CSA program has three key components: (1) the Safety Measurement System (SMS), meant to identify high-risk carriers by using data from roadside inspections and crashes; (2) interventions, which are intended to help carriers address safety problems; and (3) the Safety Fitness Determination rule. In contrast to the one investigation intervention, the compliance review, available under FMCSA’s previous approach, FMCSA expects the CSA program to more effectively change unsafe behaviors by reaching and intervening with more potentially unsafe carriers earlier using a range of intervention types to enforce compliance with safety regulations. In 2014, we reported on the effectiveness of the SMS component of the CSA program. FMCSA conducted an Operational Model Test of the program from February 2008 through June 2010 in nine pilot states. In December 2010, FMCSA began implementing the CSA program in three phases: (1) implementation of SMS and some intervention types nationwide, (2) introduction of new investigative techniques and the Safety Management Cycle, and (3) nationwide rollout of all intervention types and FMCSA’s new investigative software, the Safety Enforcement Tracking and Investigation System (SENTRI). After a series of four commercial motor vehicle crashes—two involving buses and two involving trucks—that together resulted in 25 deaths and injuries to 83 people, the National Transportation Safety Board investigated and, in November 2013, made recommendations to improve the quality of FMCSA’s compliance review processes. The Secretary of Transportation tasked the Federal Aviation Administration, as a peer of FMCSA within DOT, to conduct a review and develop appropriate recommendations for DOT’s response to the National Transportation Safety Board. The Federal Aviation Administration formed an Independent Review Team, which in July 2014, issued a report that included a range of recommendations intended to support both incremental and transformative improvements to FMCSA’s compliance and enforcement programs. We discuss some steps FMCSA is taking to address these recommendations later in this report. Under the CSA program, FMCSA can select from a range of eight intervention types, intended to give FMCSA the flexibility to address motor carriers’ specific safety problems. Four of the intervention types were newly introduced under the CSA program; FMCSA had been applying the other four intervention types prior to the program (see table 3). Each type falls into one of the following intervention categories: early contact, investigation, and follow-on interventions. Before the CSA program, FMCSA used one investigation intervention type—the onsite compliance review—and three follow-on intervention types. Compliance reviews required investigators to examine every part of a carrier’s operations and were thus extremely resource intensive to conduct. As a result, FMCSA and its state partners investigated only about 3 percent of active carriers. According to FMCSA Motor Carrier Safety Progress Reports, federal or state investigators conducted between approximately 15,000 and 17,000 compliance reviews each year from fiscal year 2006 through fiscal year 2009. Under the CSA program, FMCSA has established a process for measuring the relative safety risk of carriers in seven Behavioral Analysis and Safety Improvement Categories (BASICs), prioritizing carriers based on risk, assigning an appropriate intervention type, and investigating or enforcing compliance with regulations (see fig. 1). The CSA intervention process has no set progression, and based on existing guidance, FMCSA applies one or more interventions depending on the circumstances of each case. For example, FMCSA may directly assign an onsite comprehensive investigation to a carrier without first assigning another type of intervention. FMCSA may also apply multiple interventions to a carrier over time, and as a result, common patterns in FMCSA’s application of CSA interventions can be identified. For example, if a carrier receives a warning letter as a first intervention and its safety performance does not improve, FMCSA may assign the carrier a second intervention, such as an onsite focused investigation. If FMCSA identifies violations during an investigation, such as the onsite focused investigation, that warrant enforcement, FMCSA may assign a third intervention, such as a notice of claim. In such a case, the resulting intervention pattern would be: (warning letter) → (onsite focused investigation) → (notice of claim). Every month, FMCSA uses SMS to generate percentiles in any of seven BASICs for carriers with sufficient data. However, as we reported in 2014, the SMS methodology contains limitations that reduce FMCSA’s ability to reliably assess carriers’ safety risks because FMCSA lacks sufficient safety performance information on the majority of carriers. We identified the lack of sufficient information as a particular limitation for carriers with few inspections and vehicles because their underlying violation rates can have artificially low or high values, or greater variability, which affects the precision of the BASIC percentiles used by FMCSA in comparing carriers to one another. Nonetheless, FMCSA uses these BASIC percentiles to identify potentially risky carriers, to prioritize them for intervention, and to automatically generate warning letters. FMCSA automatically prioritizes carriers into risk-based categories of escalating urgency based on the extent to which a carrier’s BASIC percentiles exceed certain combinations of designated thresholds, in addition to the carrier’s intervention history and unresolved violations. For example, under the new high-risk definition FMCSA adopted in March 2016, for a carrier to be considered high-risk, its BASIC percentile has to be above 90 in at least two of four BASICs—unsafe driving, crash indicator, hours-of-service compliance, or vehicle maintenance—and the carrier cannot have had an onsite comprehensive investigation in the last 18 months. In addition to changing the high-risk definition, FMCSA implemented a new prioritization approach with five risk-based categories, from most to least urgent: high-risk, moderate-risk, risk, warning letter, and monitor. According to FMCSA, high-risk carriers are the agency’s highest investigative priority. After FMCSA prioritizes carriers for intervention, FMCSA division managers decide which intervention type carriers should receive based on priority level, guidance, and carrier history among other things. The principal guidance document for assigning intervention types is the electronic Field Operations Training Manual (eFOTM). Although eFOTM includes some requirements, division managers have some discretion to select investigation and follow-on intervention types based on additional information, such as complaints received, significant crashes, and professional judgment. For example, FMCSA must investigate non- frivolous written complaints that allege substantial violations regardless of whether the carrier is prioritized for intervention, but have discretion to determine the most appropriate investigation type based on the safety problems associated with the complaint, the carrier’s BASIC percentiles, and the carrier’s history. However, for carriers identified as high-risk, FMCSA must conduct an onsite focused or onsite comprehensive investigation. Federal Safety Investigators and their state partners follow eFOTM guidance when conducting investigation and follow-on interventions. In April 2013, FMCSA introduced enhanced investigative techniques (EIT) that are intended to help investigators identify the root cause of a motor carrier’s safety problems. While financial and legal penalties are typically applied following an investigation, FMCSA may levy financial penalties against a carrier without an investigation if it believes there is sufficient evidence, such as evidence that the carrier operated after being placed out of service. Investigators may also request a change to the intervention type for some carriers when they find new and pertinent information that was not available at the time of the assignment. FMCSA’s information systems are critical to its data-driven enforcement and compliance programs and are intended to provide real-time access to data for the enforcement community, the transportation industry, stakeholders, and the general public. Field staff input intervention data through a variety of field information systems. These systems are operated on laptop computers in the field. For example, field staff use the Compliance Analysis and Performance Review Information (CAPRI) system to enter investigation intervention data, such as investigatory files and safety violations identified. Similarly, they use CaseRite to enter legal enforcement information. As previously discussed, FMCSA plans to introduce a new field information system called SENTRI, which will consolidate the legacy information systems that field staff use to upload information related to interventions.