Vehicle-to-Vehicle: snapshot of the NHTSA report
But, with the announcement, US Transportation Secretary Anthony Foxx called the proposed V2V technology "the next great advance in saving lives."
The report includes preliminary estimates of safety benefits. It indicates that V2V’s two safety applications — Left Turn Assist and Intersection Movement Assist — could prevent up to 592,000 crashes a year and save as many as 1,083 lives.
Despite the existence of a number of "vehicle-resident" crash avoidance technologies already embedded in newer cars, the Transportation Department contends that V2V communications offer "an additional step in helping to warn drivers about impending danger."
V2V communications, in essence, allow cars to talk to one another, relaying such information as speed, position, and trajectory.
The advantage of V2V lies in its ability to detect distances and see around corners or even through other vehicles, according to the massive, 300-page report the US’s National Highway Traffic Safety Administration (NHTSA) put out this week accompanying its plan for V2V implementation.
According to the report, V2V-equipped vehicles "perceive some threats sooner than sensors, cameras, or radar can, and warn their drivers accordingly." V2V technology can also "be fused with those vehicle-resident technologies to provide even greater benefits than either approach alone."
Formal V2V rules won’t be released until 2016 at the earliest, when the agency is expected to publish a set of concrete proposals. By issuing advance notice of proposed rulemaking (ANPRM), both the Department of Transportation and NHTSA hope to gather significant input from the public and stakeholders.
Following pages are the summary of what’s in the report, or more specifically, what the government agencies are signaling as "work" still ahead for the industry.
In its report, NHTSA laid out several examples of crash scenarios in which V2V communications technology could be applied. The chart above shows, from top to bottom, Rear-End Collision scenarios (forward collision warning, emergency electronic brake warning), Lane Change scenarios (blind spot warning, do not pass warning) and Intersection scenarios (blind intersection warning).
Of the above, the agency identified three V2V safety applications that V2V alone can enable, and no other current, known vehicle-resident sensor- or camera-based systems can replicate. They are: Intersection Movement Assist; Left Turn Assist; and Emergency Electronic Brake Light.
Of particular note is the example of the V2V Intersection Movement Assist Warning scenario as shown below:
The agency acknowledges that two other scenarios, specifically, Forward Collision Warning and Blind Spot Warning + Lane Change Warning, are already available in production vehicles using vehicle-resident sensors.
In defense of V2V, the agency’s report makes it clear that V2V communications "offers an operational range of up to 300 meters between vehicles to facilitate identification of intersecting paths that may potentially result in a crash if no driver or vehicle action is taken."
Moreover, the agency adds, a V2V system is "not subject to the same weather, light, or cleanliness constraints associated with vehicle-resident sensors (e.g., cameras, lidar)."
However, it also notes that V2V has its own limitations, as its wireless-based communication technology is subject to issues such as urban canyons and GPS signals.
V2V communications transmit and receive messages at the 5.8 to 5.9 GHz frequency. The report, however, notes that the FCC is currently considering whether to allow "Unlicensed National Information Infrastructure" devices (such as WiFi-enabled radio, local area networks, cordless telephones, and fixed outdoor broadband transceivers used by wireless Internet service providers) to operate in the same area of the wireless spectrum as V2V.
This could become a problem.
Given that WiFi use is growing exponentially, opening up the 5.8 to 5.9 GHz part of the spectrum could result in many more devices transmitting and receiving information on the same or similar frequencies. As a result, this could lead to potential interferences with V2V communications in ways detrimental to its safety intent.
The report points out that more research needs to be done on whether these WiFi-enabled devices can share spectrum successfully with V2V, and if so, how.
Unlike ADAS integrated in new cars, the whole idea of V2V is that the communication system could be retrofitted into existing cars, without waiting for the whole population to replace their cars with new models.
In its report, NHTSA defines an OEM device for V2V as "an electronic device built or integrated into a vehicle during vehicle production." An integrated V2V system, by definition, is "connected to proprietary data busses and can provide highly accurate information using in-vehicle information to generate the Basic Safety Message." The integrated system both broadcasts and receives such basic safety messages. Once integrated into OEMs’ vehicle systems, it can offer "haptic warnings" (e.g., tightening the seat belt or vibrating the driver’s seat) and audio/visual warnings, according to the report.
Meanwhile, an aftermarket V2V communication device is defined as a device that "provides advisories and warnings to the driver of a vehicle similar to those provided by an OEM-installed V2V device."
Such an after-market device, however, may not be as fully integrated into the vehicle as an OEM device, so it could only connect to a power source, and otherwise would operate independently from systems in the vehicle.
Aftermarket V2V devices can be added to a vehicle at a vehicle dealership, as well as by authorized dealers or installers of automotive equipment.
Interestingly, the NHTSA report even predicts that some aftermarket V2V devices could be your smartphone with apps. They are "portable and can be standalone units carried by the operator, the passenger, or pedestrians."
Based on preliminary information, the report says the NHTSA currently estimates the V2V equipment and supporting communications functions (including a security management system) would cost approximately $341 to $350 per vehicle in 2020.
The cost could decrease to approximately $209 to $227 by 2058, as manufacturers gain experience producing this equipment.
Estimated costs for the security management system range from $1 to $6 per vehicle, rising over time to support an increasing number of vehicles with V2V technologies. The communications costs range from $3 to $13 per vehicle.
The report says that estimates are not expected to change significantly with the inclusion of V2V-based safety applications, since the applications themselves are software, and their costs are negligible.
The NHTSA report devoted a fair amount space to comparing traditional crash warning systems (e.g., radar, lidar, cameras, and combinations of these systems) with V2V communication technology.
The following table illustrates unique characteristics that translate into system advantages and disadvantages.
V2V safety systems use messages broadcast by vehicles to enable cooperative crash warning applications. Compared to sensors, V2V systems offer a clear advantage for field-of-view and range, the NHTSA concludes. The NHTSA believes V2V is superior because it can detect and warn of threats from any direction using a single GPS sensor and DSRC communication.
The report, however, points out concerns over basic safety-message congestion issues.
Current research has shown that V2V safety applications perform reliably in test scenarios with up to 200 vehicles in communication range. However, research conducted by the NHTSA and others has yet to estimate "the number of other DSRC-equipped vehicles that a single DSRC radio would need to be exposed to in an environment (such as heavy freeway traffic) where channel congestion would be significant."
The NHTSA report notes that V2V devices are different from other technologies regulated by the NHTSA under Federal Motor Vehicle Safety Standards. Successful operation (in terms of safety benefits) requires ensuring that a V2V unit can communicate with all other V2V devices participating in the system.
This means auto manufacturers (and V2V device manufacturers), attempting to comply with a potential V2V mandate, could have "a significant testing obligation to guarantee interoperability" among their own devices and devices produced by other manufacturers.
No one knows whether individual companies can meet such an obligation themselves, or whether independent testing facilities might need to be developed. Based on the current security design, it’s also likely that entities providing security management systems would require device manufacturers to comply with interoperability certification requirements to ensure the reliability of message content.
Right off the bat, the NHTSA report makes it clear that the V2V system "will not collect or store any data identifying individuals or individual vehicles, nor will it enable the government to do so."
It stresses that "there is no data in the safety messages exchanged by vehicles or collected by the V2V system that could be used by law enforcement or private entities to personally identify a speeding or erratic driver."
However, to create an environment of trust, a V2V system must have a security infrastructure to credential each message, and a communications network to get security credentials and related information from vehicles to system security providers (and vice versa).
In essence, "the source of each message needs to be trusted and message content needs to be protected from outside interference," says the report.
The NHTSA expects private entities to create, fund, and manage the security and communications components of a V2V system. While the NHTSA has identified several potential types of entities, including some specific companies that might be interested in participating in a V2V security system, no one in the private sector has committed to doing so.
About the author:
Junko Yoshida, Chief International Correspondent, EE Times