The number of annual fatalities and injuries due to motor vehicle crashes has declined from 42,836 fatalities and 2.8 million injuries in 2004 to 32,675 fatalities and 2.3 million injuries in 2014, although, according to NHTSA, the rate of decline has leveled off in recent years. The decline in fatalities and injuries over this time period is due in part to vehicle safety features, such as airbags. Automakers have also been installing a growing number of advanced technology features into vehicles to further improve passenger safety as well as to enhance driver and passenger convenience. For example, all vehicles manufactured starting in model year 2012 contain an electronic stability control feature that uses on- board sensors to detect and reduce skidding and automatically takes limited control from the driver to prevent the vehicle from leaving the roadway. Similarly, some new vehicles offer forward collision warning and automatic emergency-braking systems that use on-board sensors and cameras to provide warnings to the driver and in some cases assist the driver to prevent a crash from occurring. As NHTSA attributed 94 percent of highway crashes to human error in 2013, such technologies could help continue the overall decline in motor vehicle fatalities over the past decade. Driver and passenger convenience technologies include built-in navigation systems, keyless entry and ignition systems, and wireless Bluetooth capabilities, among other features. To support these and other advancements in technology, modern vehicles contain a number of electronic systems and components that have grown in number and complexity since they were first introduced into vehicles in the late 1970s. For example, a vehicle manufactured in the late 1970s contained basic electronic components to meet federal emissions regulations, and by the 1980s, the engines in most new vehicles were electronically controlled. Over time, these electronic systems have begun to replace or control many of the traditional mechanical systems in vehicles. In 2009, NHTSA reported that a typical vehicle had around 50 embedded electronic control units (ECU) responsible for executing both core vehicle functions such as steering, as well as convenience and entertainment functions. By 2014 the agency estimated that a typical vehicle contained between 70 and 100 ECUs. In addition, over time, ECUs have evolved from controlling a single vehicle function and operating in isolation from other components, to controlling multiple vehicle functions and operating in conjunction with one another. To facilitate communication among multiple ECUs without the need for complicated and extensive wiring systems, automakers began locating ECUs on in-vehicle communication networks, commonly referred to as buses or bus systems. According to NHTSA, the controller area network (CAN), which was first developed in 1985, has become the most commonly used in-vehicle communication network or bus; however, other types of networks are used by some automakers. The CAN was designed to ensure that ECUs within the vehicle could reliably and expediently send messages to one another. The specific configuration of CAN and other in-vehicle communication networks can vary widely across automakers and even across different models produced by a single automaker, depending on the number and types of features within the vehicle. For example, automakers may locate all ECUs on a single in- vehicle network or include one network to support safety-critical vehicle functions, such as steering and braking, and another network to support convenience and entertainment systems. Figure 1 illustrates how in- vehicle communications networks reduce the need for wiring while facilitating communication among ECUs. While the shift from mechanical to electronically-controlled vehicle systems has helped improve the reliability and performance of certain vehicle features and allowed automakers to introduce new safety and “infotainment” features that are popular with consumers, it has also increased the potential for vehicles to be affected by cybersecurity breaches more commonly associated with the information technology (IT) and financial services industries. In particular, as the number of ECUs and electronic systems in vehicles has increased, the prevalence of software code in vehicles has also increased dramatically—and in some cases exponentially. DOT publications have indicated that a modern luxury vehicle could contain as much as 100 million lines of software code. In comparison, a Boeing 787 Dreamliner has about 6.5 million lines of software code (see fig. 2). According to researchers and others, the use of software in vehicles is likely to increase as more advanced vehicle technologies and connected vehicle technologies are incorporated. As the lines of software code in vehicles increases, so does the potential for software errors, such as coding errors, and related vulnerabilities. According to NHTSA, in the context of motor vehicles, cybersecurity is the protection of automotive electronic systems, communication networks, control algorithms, software, users, and underlying data from malicious attacks, damage, unauthorized access, or manipulation. Although no vehicle cyberattacks impacting passenger safety have been reported outside of the research environment, our previous work has shown that the sources of cyber-threats vary in terms of the types and capabilities of the actors, their willingness to act, and their motives. For example, hackers break into networks for the thrill of the challenge, bragging rights in the hacker community, and monetary gain, among other reasons, whereas botnet operators use a network of compromised, remotely- controlled systems to, among other things, coordinate attacks, such as denial-of-service attacks that prevent the authorized use of networks, systems, or applications by exhausting resources. Still others, such as nations may use cyber tools for information-gathering and espionage activities, while terrorists may seek to cause harm or damage public morale and confidence. Responsibility for ensuring the security of vehicle systems and components spans across the automotive supply chain and occurs throughout the vehicle development cycle. For example, automakers define core vehicle design requirements, including software system requirements, to automotive parts suppliers. In turn, automotive parts suppliers assemble vehicle systems and often rely on lower-level suppliers, such as chip manufacturers, to obtain the specific parts (i.e., hardware) for the vehicle systems. Each supplier is responsible for testing and validating its specific product and certifying that its product meets automaker specifications. Automakers may incorporate components from multiple suppliers to assemble the vehicle and are ultimately responsible for validating that safety-critical systems meet minimum performance requirements and operate as intended. Within DOT, NHTSA is the primary agency responsible for vehicle safety. NHTSA’s mission is to save lives, prevent injuries, and reduce economic costs due to road traffic crashes. NHTSA developed Federal Motor Vehicle Safety Standards, which establish the minimum performance requirements for certain safety features, such as brakes and air bags, to which automakers must conform and certify compliance. NHTSA also conducts research in support of vehicle safety programs. The Office of Vehicle Safety Research conducts research in the areas of crashworthiness, crash avoidance, and electronic controls research. The electronic controls research—which includes research in the areas of electronics reliability, automated vehicles, and cybersecurity—is conducted by the Electronics Systems Safety Research Divisionand is also supported by VRTC, the agency’s in-house laboratory, in East Liberty, Ohio. In fiscal year 2015, the Office of Vehicle Safety Research had a budget of $29 million, of which $2.5 million was dedicated to electronics and vehicle cybersecurity research. According to NHTSA officials, as of July 2015, five full-time staff were dedicated to vehicle cybersecurity, automation, and electronics research. In addition, NHTSA has research under way related to cybersecurity for connected-vehicle technologies, which, as previously mentioned, are expected to provide safety benefits by deterring crashes. Several recent laws and legislative proposals have included provisions related to vehicle cybersecurity. For example, MAP-21—which was signed into law in July of 2012—directed NHTSA to, among other things, complete an examination of the need for safety standards with regard to electronic systems in passenger motor vehicles and to consider various topics, such as the security needs for those electronic components to prevent unauthorized access. The act also required NHTSA to seek public comment in conducting its examination and to issue a report to Congress on the highest priority areas for safety with regard to electronic systems. In addition, the Fixing America’s Surface Transportation Act (FAST Act), enacted in 2015, requires DOT to submit a report to Congress on the operations of the Council for Vehicle Electronics, Vehicle Software and Emerging Technologies (Electronics Council), which was established in MAP-21 to provide a forum for research, rulemaking, and enforcement officials to coordinate and share information internally on advanced vehicle electronics and new technologies. Legislative proposals related to ensuring vehicle cybersecurity have also been introduced by members of Congress. For example, if passed, the Security and Privacy in Your Car Act of 2015 would require NHTSA to establish a “cyber dashboard” that displays an evaluation of how well each automaker protects the security and privacy of vehicle owners and would require automakers to adhere to government standards for vehicle cybersecurity. The Security and Privacy in Your Car Study Act of 2015 would require NHTSA, along with some other federal agencies, to conduct a study to determine the appropriate standards for the regulation of vehicle cybersecurity. Finally, other federal agencies and foreign governments have also conducted cybersecurity research, particularly as it relates to connected- vehicle technologies, which are expected to increase the need for security protections. For example, the European Union sponsored two major projects examining the security of connected-vehicle technology communications. These projects resulted in guidelines for the various security elements needed for the deployment of connected-vehicle technologies, such as message integrity, privacy protection, and misbehavior detection. Based on our analysis of research and industry stakeholder views, modern vehicles contain multiple interfaces—connections between the vehicle and external networks—that if not properly secured, can become entry points—or attack paths—for cyber attackers. Some of these interfaces can only be accessed through direct contact with the vehicle, while others can be accessed remotely through short- and long-range wireless channels. Selected industry stakeholders we interviewed identified several vehicle interfaces that can be compromised through direct, physical access to a vehicle (see fig. 3).