About 5.3 million car and truck accidents occurred on U.S. roads in 2011, resulting in some 32,000 fatalities and more than 2.2 million injuries. Although those road-casualty numbers have been falling in recent years as vehicles are built increasingly safer, the world’s automotive industry, in cooperation with the U.S. Department of Transportation (DOT) and its foreign-government counterparts, has been working to develop vehicle-to-vehicle (V2V) safety technologies that can warn drivers of imminent road collisions by sharing with nearby vehicles data from onboard crash-avoidance sensors as well as information on vehicle speed and location.
V2V communications has progressed to the point that real-world pilot testing is ongoing in Japan, Germany, and the U.S., and hopes are high that these technologies can eventually offer significant safety advantages. DOT studies indicate, for example, that broad deployment of V2V and the related vehicle-to-infrastructure (V2I) technologies could provide warnings to drivers in three-quarters of potential multi-vehicle collisions.
To gauge the current state of V2V, the U.S. Congress asked the Government Accounting Office (GAO) to review the technology’s engineering and commercial status. “We contracted with the National Academies of Sciences to identify 21 non-government experts on connected-vehicle technologies to survey in structured interviews,” said Dave Wise, Director of the GAO’s Physical Infrastructure Team. The GAO, in addition, reviewed related DOT documentation and spoke with a V2V-device supplier, experts from DOT, OEM members of the Vehicle Infrastructure Integration Consortium, and the Crash Avoidance Metrics Partnership, as well as representatives of auto industry and public interest groups that monitor V2V technologies. Members of the GAO team also observed demonstrations of V2V systems and visited the Safety Pilot Model Deployment that is now taking place in Ann Arbor, MI.
The auto industry has so far focused on developing in-vehicle components such as hardware to facilitate communications among vehicles, safety software applications to analyze data and identify potential collisions, vehicle features that alert drivers, and a national communication-security system to ensure trust in the data transmitted among vehicles.
Wise noted that continued advancement of V2V and other intelligent highway systems technologies hinges on a decision that the U.S. National Highway Traffic Safety Administration (NHTSA) plans to make late this year on how to proceed with the technology, including setting the time frames for implementation as well as continued development.
For the report, the GAO examined the state of the art in V2V technologies and their anticipated benefits; the challenges that will affect the deployment of these technologies and what actions DOT is taking to address them; and what is known about the potential costs associated with these technologies, he explained. The document is available at www.gao.gov/assets/660/658709.pdf.
Communication security issues
“In general, the experts and others we interviewed see few technical challenges remaining in development of V2V systems,” Wise observed. “And although in-vehicle V2V components are far along in development, the security system to protect their wireless communications needs more work.” It is also clear that “the actual benefits of the technology will depend on V2V-deployment levels, how well drivers respond to V2Vs, and the deployment of other safety technologies that can provide similar crash-avoidance benefits.”
V2V’s safety benefits will be maximized by deploying the technology throughout the entire domestic vehicle fleet, according to DOT. But even if NHTSA pursues a rule that requires the inclusion of these technologies in new vehicle models, years would likely pass before they are fully realized because of the time needed for the fleet to turn over, which could take as long as two decades. Aftermarket V2V devices for existing vehicles could help speed deployment, it is thought, although a few of the experts said that the adoption of aftermarket system may be limited because drivers may not truly appreciate their value.
Any benefits that derive from V2V technologies will also depend on drivers’ response to warning messages. Furthermore, if the safety systems issue too many false warnings, drivers could begin to ignore valid ones. The report also found that any potential benefits are contingent on the continuing market penetration and growing effectiveness of onboard crash-avoidance technologies based on sensors such as cameras and radars.
Remaining technical hurdles
“The experts indicated that the major challenges to deployment of V2Vs include defining technical and management structure of the communications-security system, addressing privacy issues, human factors concerns, and potential unique liability matters,” Wise said.
A security system that can detect, report, and revoke the credentials of networked vehicles found to be disseminating inaccurate information will be needed to ensure trust in the data transmitted among vehicles. Final plans and policies for the V2V communications-security system—including its technical framework and management structure—have yet to be determined and will need to be finalized before deployment begins.
More than half of experts called the technical development of a V2V communication-security system a "great" or "very great" challenge. One of those interviewed said that it will be difficult to establish technical specifications for a system that maintains users’ privacy as it provides security for wireless data transmission. Another expert told the GAO that a public infrastructure system of the scale required to support the nationwide deployment of V2V technologies has never been developed.
A half-dozen car makers and 17 experts expressed concern about uncertainties related to potential legal liability regarding collisions involving V2V-equipped vehicles. One manufacturer noted that the fact that V2V technologies provide warnings that are based in part on data transmitted by other vehicles, as opposed to onboard sensor-based systems, could make it harder to determine whether fault for a collision between V2V-equipped vehicles lies with drivers, automakers, device manufacturers, or some other party.
“The other big unknown at this time are costs,” Wise stated. “The OEMs report that they have done limited work to estimate potential costs. However, it does look like the potential costs of in-vehicle equipment are likely to be relatively limited compared to the costs of new vehicles.” On the other hand, “the potential costs of a communications-security system may be more significant, so it’s no surprise that the DOT and the industry have efforts under way to estimate those costs.”
Furthermore, it is currently unclear who among consumers, automakers, federal/state/local governments, or others would pay the costs associated with a V2V communication-security system.