Although there were about 32,000 motor vehicle traffic fatalities in the United States in 2011, the number has generally declined in recent years. According to NHTSA, the rate of 1.10 fatalities per 100 million vehicle miles traveled in 2011 represented an all-time low and was 28 percent lower than the rate of 1.52 in 2001. DOT has attributed reductions in fatality rates to several factors, including increased use of in-vehicle safety features such as safety belts and a reduction in fatalities related to alcohol-impaired driving. In recent years, automobile manufacturers have begun to equip some newly manufactured vehicles with sensor-based crash avoidance technologies intended to prevent accidents and further reduce the number of fatalities. These technologies employ sensors such as cameras, radio detection and ranging, and light detection and ranging to observe a vehicle’s surroundings. A vehicle equipped with such technologies is capable of detecting potential collisions with other vehicles or obstacles within a range of about 150 meters (about 500 feet) and alerting drivers through applications such as forward collision warnings and lane departure warnings; however, such warnings are limited to the threats within the field of view of the vehicle’s sensors. DOT has worked with the automobile industry and others to lead and fund research on connected vehicle technologies, which include V2V technologies as well as vehicle-to-infrastructure technologies. From fiscal years 2003 through 2012, the funding DOT has made available for efforts on connected vehicle technologies, part of its Intelligent Transportation Systems (ITS) research program, totaled about $445 million and ranged from a low of $17 million in 2008 to a high of $84 million in 2011. In a connected vehicle environment, data is shared wirelessly among vehicles (V2V communications) or between vehicles and infrastructure (vehicle-to- infrastructure communications) using dedicated short-range communications (DSRC), a technology similar to Wi-Fi that offers a link through which vehicles and infrastructure can transmit messages over a range of about 300 to 500 meters (about 1,000 to 1,600 feet). Based on analysis of internal data and data received from other vehicles, a vehicle equipped with V2V technologies is able to issue a warning to its driver when a collision with another similarly equipped vehicle could occur. The range of V2V communications is not only greater than that of existing sensor-based technologies, but due to the sharing of data between vehicles, V2V technologies are capable of alerting drivers to potential collisions that are not visible to existing sensor-based technologies, such as a stopped vehicle blocked from view or a moving vehicle at a blind intersection (see fig. 1). While V2V technologies send and receive data among vehicles, vehicle- to-infrastructure technologies send and receive data between vehicles and infrastructure, such as traffic signals. Vehicle-to-infrastructure technologies could offer additional safety features that V2V technologies cannot, such as providing drivers with additional warnings when traffic signals are about to change, warnings that could help reduce collisions at intersections. In addition, these technologies can offer potential mobility and environmental benefits; for example, they can collect, analyze, and provide drivers with data on upcoming roadway and traffic conditions and suggest alternate routes when roadways are congested. In addition to federal efforts, automobile manufacturers have formed a number of consortia to research and develop V2V communication-based technologies and have collaborated with DOT on these efforts. Since 2002, DOT has awarded $77 million in funding, under cost-sharing agreements to support projects related to V2V technologies, to a number of consortia established by the Crash Avoidance Metrics Partnership (CAMP). This partnership between Ford Motor Company and General Motors, L.L.C. is currently working with 6 other automobile manufacturers through the Vehicle Safety Communications (VSC) 3 Consortium to collaboratively address safety issues through advancements in vehicle communications. Additionally, the Vehicle Infrastructure Integration Consortium (VIIC) was created in 2005 and is currently comprised of 10 automobile manufacturers with the goal of identifying and promoting policy solutions needed to support the development and deployment of V2V and vehicle-to-infrastructure technologies. The automobile industry (as well as some technology companies such as Google) is also working to develop autonomous vehicle technologies, which would control steering, acceleration, and braking without a driver’s input. Some automobile manufacturers have started to introduce semi- autonomous sensor-based technologies capable of reducing a vehicle’s speed through adaptive cruise control or even stopping a vehicle through automatic braking when a collision is imminent. Autonomous vehicles are being designed with the intent that a driver is needed to provide destination or navigation information, but not needed to control the vehicle. Because V2V communications depend upon DSRC technology to transmit data among vehicles, the deployment of V2V technologies will require use of the radio-frequency spectrum. FCC has allocated spectrum for use by DSRC technologies that are part of DOT’s ITS research program. Specifically, in 1999, FCC allocated 75 megahertz (MHz) of spectrum—the 5.850 to 5.925 gigahertz (GHz) band (5.9 GHz band)— for the primary purpose of improving transportation safety and adopted basic technical rules for DSRC operations. In 2003, FCC established licensing and service rules for the 5.9 GHz band to provide a short-range, wireless link for transferring information between vehicles and roadside systems. However, the President and Congress have responded to growing demand for wireless broadband services by making changes in the law to promote efficient use of spectrum, including the band previously set aside for use by DSRC-based technologies. For example, the Middle Class Tax Relief and Job Creation Act of 2012 required the National Telecommunications and Information Administration (NTIA) to conduct a study evaluating spectrum-sharing technologies and the potential risk to federal users if unlicensed devices were allowed to operate in the 5.9 GHz band. Given the potential benefits of V2V technologies, NHTSA has said it will decide by the end of 2013 how it will proceed with respect to these technologies for passenger vehicles. According to NHTSA officials, they are considering several possible actions, including announcing NHTSA’s intent to pursue future regulatory action, such as a proposed rulemaking to mandate the installation of these technologies in newly manufactured passenger vehicles and continuing to research and develop these technologies for passenger vehicles. Efforts by DOT and the automobile industry to develop V2V technologies have reached the point at which they have been tested in a 12-month, real world pilot that will conclude in February 2014. These efforts have focused on developing and testing needed components including hardware to send and receive data among vehicles, software applications to analyze data and identify potential collisions, vehicle features that issue warnings to drivers of these potential collisions, and a security system to ensure trust in the data that are being communicated among vehicles. According to DOT, once deployed, V2V technologies have the potential to address—by providing warnings to drivers—76 percent of all potential multi-vehicle crashes involving at least one light-duty vehicle. However, the potential benefits of V2V technologies are dependent upon a number of factors including their deployment levels, how drivers respond to warning messages, and the deployment of other safety technologies that can provide similar benefits. Recent and ongoing V2V technology development efforts have been working toward the expected late 2013 NHTSA decision as the next major milestone. DOT, for example, has focused on research and analysis that can provide input for and facilitate its upcoming decision. Most of the 21 experts and 9 automobile manufacturers we spoke with told us that they expect NHTSA’s decision to help determine the progress of continued development and eventual deployment of V2V technologies. Development of these technologies has progressed to the point of real world testing. DOT has sponsored and provided approximately 80 percent of the funding for a pilot test called the Safety Pilot Model Deployment (Safety Pilot). This project—in which DOT has partnered with the CAMP VSC 3 Consortium—has been conducted by the University of Michigan Transportation Research Institute and is taking place in Ann Arbor, Michigan, from August 2012 to February 2014. The primary goals of this pilot are to test the effectiveness of V2V technologies in real world situations and to measure their potential benefits. In total, about 2,700 passenger vehicles were equipped with these technologies in order to participate in the Safety Pilot. NHTSA plans to release findings from the Safety Pilot in the fall of 2014. DOT is considering the data from the first 6 months of the pilot, along with other information, in working toward a decision by late 2013 on how to proceed with V2V technologies. Efforts by DOT and the automobile industry to develop V2V technologies have focused on both in-vehicle components as well as a security system that manages V2V communications and ensures trust in the data being transmitted among vehicles (see fig. 2). Examples of in-vehicle components include: V2V hardware, including DSRC radios, cables, and antennae to send and receive data and GPS chips used to determine vehicle location. Software applications that analyze data such as location, speed, and brake status and, based on that analysis, predict when collisions are imminent. DOT has worked with automobile manufacturers to determine the most relevant applications based on common crash scenarios and to define, develop, and test these to inform and support NHTSA’s V2V technology decision later this year. A driver-vehicle interface that—based on the data analysis conducted by the V2V software applications—provides a warning to the driver through vehicle features such as sounds, lights, or seat vibrations when a collision may be imminent. Existing sensor-based crash avoidance technologies also provide warnings to drivers through similar mechanisms. DOT has been developing guidelines for automobile manufacturers in implementing driver-vehicle interfaces. In addition to in-vehicle V2V components, an external communication security system is needed to ensure that data being transmitted among vehicles are secure and trusted and have not been altered in the transmission process.