Imagine that you are driving at speed behind a big truck. Unknown to you, a car precedes the truck. Suddenly the driver of the lead car hits the brakes hard. Whether you rear-end the truck depends on three things: your speed, the distance to the truck, and how fast you can react to the illumination of its brake lights. One thing that has little to do with your outcome is whether your car has collision-avoidance radar or not. That’s because, just like your eye, radar can only sense objects that it can see.
Say, on the other hand, that 10 times a second each of three vehicles is broadcasting a safety status report via short-range Wi-Fi. Suddenly the lead driver slams the brakes. This time the lead car’s emergency stop signal and GPS location is transmitted instantly to your car’s own digital safety monitor, which rapidly calculates that a collision is imminent. The monitor immediately triggers an unmistakable stop sign—a strip of bright red LEDs on your dashboard. Your chances of missing the truck have improved considerably.
Such advanced safety technology, known as vehicle-to-vehicle (V2V) communications, lies just around the bend, according to Michael Shulman, a technical leader at Ford's Active Safety Research and Advanced Engineering Department, who is heading the company’s effort to field-prototype V2V-equipped vehicles within a couple of months.
“V2V can improve the driver’s situational awareness through advisories, notifications, and warnings of unseen road hazards,” he stated, citing a report issued last fall by the U.S. NHTSA that indicated that each year several million vehicle-on-vehicle crashes, around fourth-fifths of all such accidents involving unimpaired drivers, could possibly be prevented “if vehicles just talked to one another.”
Beyond sudden stops, the new technology could alert drivers when two cars are on a collision course at a blind intersection or when a nearby driver changes lanes without looking or loses control. This cooperative wireless link could also warn motorists of less critical issues such as an imminent yellow light or traffic congestion or road conditions.
And not only can V2V help save drivers, it can do so affordably, Shulman said. “The nice thing about V2V communications is that it’s relatively low-cost. No exotic technology is needed, only a special flavor of Wi-Fi communications and GPS.”
The other big piece of the puzzle, the necessary digital control smarts, have already been developed for collision avoidance and automatic cruise control (ACC), radar-based systems that can cost thousands of dollars to install, he continued. “This means that all cars, not just luxury ones, can have this capability; we want to sell this technology on the Fiestas as well as the Lincolns.”
Although enhancing safety—accident avoidance—is Ford’s priority, V2V can also bring other significant customer benefits in a variety of applications related to eco-mobility, infotainment, and driver convenience, Shulman observed. “We want to be the leader in network-connected vehicles and in bringing these new benefits to the customer.” He noted that Ford management has doubled its investment in intelligent, connected vehicles and has assembled a task force of 20 personnel, including planners, engineers, and scientists, to accelerate development of the new comm link. “We plan on becoming the first automaker to build prototype vehicles for demonstrations across the U.S. in the spring,” he said.
Shulman added that his team is busy readying eight prototype Taurus sedans with V2V communications systems that are targeted for delivery to the U.S. DOT early this summer. The cars will be part of a fleet of 64 equipped vehicles that are being supplied by a variety of makers for a government/industry pilot program to evaluate and road-test V2V technology. Also included in the pilot effort will be V2V’s cousin, vehicle-to-infrastructure (V2I) systems—vehicle communication with road fixtures such as traffic signals and toll booths. As part of the demonstration program, the DOT will sponsor development of inexpensive aftermarket V2V devices that can be retrofitted to existing vehicles.
The DOT is mounting the R&D effort because its administrators believe that the technology provides one of the most effective pathways to improved road safety. “This technology is an opportunity to help create a future where millions of vehicles communicate with each other by sharing anonymous real-time information about traffic speeds and conditions,” said Peter Appel, head of the DOT’s Research and Innovative Technology Administration. “This new world of wireless communication will make transportation safer, provide better and faster exchange of information for vastly improved daily and long-distance travel, and even reduce environmental pollution.”
Also taking part are state and local highway authorities, who are looking for ways to obtain good, real-time traffic information from these distributed networks. This data would truly help them manage congestion and improve mobility on their roads, Shulman said. “If drivers could report their recent travel history in a private way, the authorities could react to problems much faster and the network could provide timely alerts to motorists.”
Crossroads for V2V
This year seems to mark a crossroads for V2V and V2I technology as recent advancement is the culmination of years of cooperative, precompetitive work by industry and government to prepare the promising safety technology for introduction. The current state of progress was arrived at through eight years of joint efforts by car companies (Daimler, Ford, General Motors, Honda, Toyota), government agencies (DOT and NHTSA), and professional organizations (SAE International and IEEE). The initial industry-wide cooperation came naturally because of the inherent cooperative nature of this technology, especially given that the benefits of V2V and V2I will only start to manifest themselves when a reasonable fraction of the vehicles on the road are suitably equipped.
The joint V2V effort started in 2002 when the FCC allocated radio spectrum for dedicated short-range communications (DSRC) to enable cars to talk to other cars and the road infrastructure (a 75-MHz spread on a 5.9-GHz carrier wave), Shulman recalled. “The concept was to communicate within 300 meters, and unlike radar, you could take advantage of the fact that V2V doesn’t need direct-line of sight,” he said. “To convince ourselves of its feasibility, the five companies did tests like sending 1000 packets at speed in bad weather to see how many were received,” he explained. The rigorous evaluations showed that the link “was pretty robust, which persuaded us that V2V will really work and is worth implementing.”
The industry, he continued, agreed to build V2V using a version of Wi-Fi that was described in the IEEE 802.11p standard, a carrier-sense multiplex-access protocol. Other relevant standards are an interim IEEE 1609 protocol and SAE J2735, which “has to do with what should be in the basic message set.” Working with DOT experts, the coalition decided that a message would include such things as a vehicle’s position, speed, brake status, path prediction, path history, vehicle mass, and bumper height.
“This message is sent out 10 times a second by every equipped vehicle, which enables your system to place and plot out surrounding vehicles in space and receive messages about potential hazards,” Shulman explained. Along with NHTSA specialists, company engineers identified traffic scenarios in which V2V could improve safety: forward collision warning, emergency electronic braking, blind spot warning, lane change warning, do not pass, and control-loss warning. He stressed that “V2V and V2I allow safer operations at intersections, a place where it’s really tough to improve safety.”
A secure and private network
“Of course, we don’t want anybody tracking drivers or any law enforcement involvement,” he said, “so everyone’s ID only lasts five minutes and then it changes.” This scheme retains enough short-term linkability to deliver services but maintain anonymity. The designers also ensured that the network could maintain security from attack by malicious users or hackers by installing PKI (public key infrastructure) cryptographic systems.
Shulman said that the public-private partnership has a clear road map to finish up all remaining research and standards and then move on to institute regulations (“a rule-making process”). “We still need a standard to be set on congestion management, that is, what happens when you’re in traffic and there are 100 cars within 300 meters. If everybody transmits 10 times a second you fill up the channel,” he explained. The system will probably reduce power or message frequency in that case.
“V2V is a very interesting application,” Shulman concluded. “Current developments show that the industry is transitioning from cooperation to competition. Everyone must cooperate to make the system work to improve safety, but here at Ford we’re also trying to differentiate ourselves by focusing as well on the human-machine interface as well as a range of unique and exciting convenience apps for the customer.”