Potholes abound on the road to car-to-car communication

Early on the last morning of CES, I found myself in a Las Vegas parking lot signing a liability waiver. I was there for a ride in a modified Ford Taurus carrying what could be the future of driving in America: a system that alerts drivers of potential accidents by talking to other cars.

After going through a number of scenarios, the driver of the Taurus pulled up to a simulated intersection. As the light changed and the driver went to pull through, an alarm sounded on the dash and he braked—just as another car in the demo, previously blocked from view by a parked container, shot through its red light.

In the real world, I would have been praying that the side-impact airbags would protect me. But in this version of a future US roadway, I was saved by radio signals sent by the car running the light, alerting the Taurus that a collision was imminent. “When you look at what causes accidents, about 90 percent are due to driver error,” said Michael Schulman, the technical leader for vehicle communications in Ford’s Active Safety Research and Advanced Engineering group. “Mostly drivers are distracted, or they just have bad judgment, or they’re impaired. So this is meant to be a first step to see how we can warn them. The car is always exchanging messages with other cars, and just in that rare case when I need it, I get a warning.”

For the past decade, engineers from a host of auto companies—including Ford, GM, Honda, Toyota, Nissan, Daimler, Volkswagen Group, and Hyundai Kia—have been collaborating on the next step in vehicle safety. The system, called vehicle-to-vehicle (V2V) communications, or Dedicated Short-Range Communications (DSRC), will allow cars to share data that can alert drivers to prevent the most common—and most fatal—multi-vehicle accidents on American roads.

The idea behind V2V is fairly simple, and it’s based on technology that is already part of many new cars—it’s just put together in a different way. Tested in a 3,000 car trial in Ann Arbor, Michigan over the past three years, the system uses a variant of Wi-Fi technology, GPS data, and vehicle data already collected by sensors in many vehicles to broadcast information that can warn other vehicles of a potential crash.

Just how soon this technology will hit the streets is still an open question, however. V2V is largely ready to go. And last year, the National Highway Traffic Safety Administration (NHTSA) seemed poised to mandate the technology in every vehicle. “NHTSA has to make a decision about [if it’s] going to proceed toward a regulation that would require this on new cars,” said Schulman.

But that announcement has been held up. And part of the reason may be the leaks from former National Security Agency contractor Edward Snowden and the heightened awareness among both citizens and legislators of government surveillance. “Given what’s happened with the NSA,” Schulman said, “I think they felt, ‘If an announcement came out tomorrow, people are going to freak out.’”

The unfinished roadmap

Some of the scenarios V2V is designed for, from a Government Accountability Office report on the Department of Transportation program.

Credit: Government Accountability Office

Officially, the NHTSA would only issue the following statement on V2V: “The Department of Transportation and NHTSA have made significant progress in determining the best course of action for proceeding with additional vehicle-to-vehicle communication activities and expect to announce a decision in the coming weeks.” Sources at the NHTSA say that the agency simply hasn’t finished all of the supporting work needed to support a decision on V2V yet.

When that decision does come, many in the industry believe it will be the first step in a much broader transformation of the nation’s transportation system. It will seed the creation of a network that not only prevents automobile accidents but also turns vehicles into data collectors. It would make it possible for traffic management systems to use vehicle-to-infrastructure (V2I) communications to monitor congestion and deliver information to vehicles that improves traffic flow.

V2V and V2I are also seen as a necessity in the development of truly autonomous cars, allowing robotic vehicles to negotiate with each other to handle traffic flow. They could improve public transportation and provide countless other benefits to both drivers and governments.

But what worries some is that the system could be used to target “bad actors” on the highways, as they were referred to in a recent Government Accountability Office (GAO) report. Cars may become informants on drivers who speed or drive erratically, though the Department of Transportation says that the data will be purely anonymous and not used for those purposes.

There are already some with privacy concerns about location and other data being collected by automakers. Senator Al Franken of Minnesota recently wrote a letter to Ford executives requesting clarification on the company’s practice of collecting GPS data from vehicles. That request came after Ford Global Vice President of Marketing Jim Farley said that for drivers in Ford vehicles equipped with GPS and Sync, “We know everyone who breaks the law, we know when you’re doing it. We have GPS in your car, so we know what you’re doing. By the way, we don’t supply that data to anyone.” That came at CES, but Farley has since said that Ford does not track customers in their cars without their approval or consent. But the capability to do so still exists, as systems like Sync and GM’s OnStar collect more data behind the scene as part of navigation and safety features.

V2V ups privacy concerns because it essentially broadcasts a vehicle’s location and speed, as well as some information about where a vehicle has been previously, to anyone within range. And while Department of Transportation officials told the GAO that “V2V communication security system would contain multiple technical, physical, and organizational controls to minimize privacy risks—including the risk of vehicle tracking by individuals and government or commercial entities,” regulating who can use V2V data and for what would fall outside the Department of Transportation’s span of control. It would essentially require legislation by Congress.

And even after the NHTSA makes a decision on a way forward with V2V—if it decides there is a way forward—privacy concerns aren’t the only problems left to overcome.

Integrating V2V systems with new car designs may be relatively simple. The current platform for V2V is based on well-understood technology, such as automotive-grade GPS, radio technology based on the underlying standards of Wi-Fi, and event sensors that already report data such as a car’s pitch and yaw. A vehicle’s current warning systems—lights, alarms, and in some cases “haptic feedback” systems such as vibrating seats—are already in production in vehicles equipped with anti-collision radar and other sensors. But integrating V2V into existing vehicles could be complex and expensive.

Getting in gear

The many components of V2V communications systems.

Credit: GAO

In 1999, the Federal Communications Commission designated a band of radio frequency around 5.9GHz for use in communication between cars and infrastructure. It’s also a range used by satellite and military communications systems, so it’s not exclusively the domain of V2V, but the limited range of the communications systems reduces concerns about interference.

While the spectrum was there, development of standards for V2V didn’t begin in earnest until 2002. That work has focused on the 802.11p wireless protocol—a modification of the 802.11 standard used by Wi-Fi wireless networks. 

Using 802.11p broadcasts from omnidirectional antennas, V2V systems have a range of about 250 meters (a little more than 820 feet). “We send out a short message on one channel of that band that says ‘here’s my position, here’s my speed, here’s my yaw rate, and here’s my acceleration—the vehicle’s state,’” said Schulman. “You actually keep sending it out even if there’s no one around you.”

That constant broadcast could be useful for a number of applications with goals beyond just preventing collisions. “Your car could act like a traffic probe and report back to a central traffic management center—some anonymized data that says ‘here’s the path I took and how long it took me to get there,’” said Schulman. “That could be aggregated, and traffic centers would have a lot of real-time information about where congestion is. They could use that to time the lights, to do ramp metering, to give people better routes. We could connect up public transportation so people could look at where they want to go, what their choices are, how long each would take, and how much it would cost—all based on real information.”

In 2012, the NHTSA sponsored a large-scale test of V2V and some V2I technology in Ann Arbor, Michigan. A total of 3,000 cars, some with factory-installed V2V systems and some with systems integrated “after market,” were let loose on the streets of the city for normal use. “It worked pretty well,” said Schulman. “There were some issues, but it was very early technology.”

If the NHTSA goes forward with developing a regulation on V2V—which could be defined by 2016—systems could be a requirement in most cars by 2018. And that would be the impetus for a revolution in infrastructure systems, Schulman said. “My sense is that it will grow like hotspots grew when laptops started having Wi-Fi built in—cities and countries will start to invest in it. Some places will be more progressive than others. It may not be in Montana as quickly as Boston, but eventually we’ll see it around the country.”

The Federal Highway Administration is on board with that thinking to the tune of $45 million, funding a joint auto industry program to start developing V2I applications. Some proposed uses include a system that communicates with city parking systems, using travel data and destination information to determine when a car will arrive and reserving a parking spot for it.

The biggest hurdle most cities and counties will face in installing these kinds of systems is likely the financial hit. The GAO study noted that the cost of roadside V2I equipment “could range between $25,000 and $30,000 per installation.” And that figure doesn’t include the backend costs of operating and maintaining them.

But there are a number of limitations to V2V technology that could create challenges, both from a safety and policy standpoint. One of them is simply preventing the system from being hijacked by bad data.

Certified to drive

Creating a national requirement for even just some classes of vehicles to carry V2V systems will create the need for a whole new level of national information infrastructure. This would make sure the system isn’t used maliciously to spoof traffic data, creating false alerts or potentially even accidents.

The security design of the system as implemented in tests so far will require a national certificate infrastructure much like that used for preventing domain spoofing and securing the Web. It will require a database of certificates—like the X.509 certificates used in public key infrastructure (PKI)—to verify that devices are legitimate and make it possible to rescind permissions to ensure that no one can send out spoofed messages. If a certificate were to become compromised or if a manufacturer misconfigured a batch of V2V systems, the certificate authority would be able to revoke the associated certificate. This prevents spoofing much in the way that DNS SEC prevents the “poisoning” of Internet domain address tables by a rogue Domain Name Service server.

The problem is that no one has ever developed a PKI system large enough to handle every vehicle in the United States—every car, truck, bus, and motorcycle. The revocation table for expired or compromised certificates would have to be distributed constantly to cars to make sure they weren’t victimized by recorded data attacks or other systems that used hacked hardware to spoof traffic.

So far, there hasn’t been any agreement yet on how this PKI would distribute its certificates. Proposals have included having roadside systems issue certificates as vehicles drive by and having certificates sent to vehicles out-of-band over cellular connections. The latter would mean that every car in the country would have to have its own integrated cellular phone or that drivers would have to connect their phones regularly to the systems to ensure they didn’t get shut out of the network.

The certificates in the system would theoretically be anonymous. They would not be tied to specific identifying information about drivers or their vehicles. Even so, certificates could be potentially used to create “fingerprints” for vehicles passing through a V2I network’s mesh of antennas even without an explicit connection to the driver. Certificate information could be combined with traffic cameras and other sensors, connecting the certificate to other data including their speed, lane changing behavior, or even travel routes.

Other questions include who is put in charge of the certificate system and who pays for it. Putting it under federal control would allow for more direct regulation of privacy, but it would be hugely expensive. And because there’s no real idea of what the capacity requirements will be for communication between cars and the certificate system, and because it’s not known who will operate it, the GAO found, “it is currently not only difficult to estimate the potential costs, but unclear who or what entity—consumers, automobile manufacturers, the Department of Transportation, state and local governments, or others—would pay the costs. Determining who or what entity will fund the system will likely prove challenging.”

Blind spots

Another, potentially larger problem facing V2V and V2I is the threat to the spectrum that the services would be tied to. The President’s Council of Advisors on Science and Technology has pushed to take the spectrum away from the Department of Transportation and free it up for use in broadband wireless Internet service. As part of the Middle Class Tax Relief and Job Creation Act of 2012, Congress required the National Telecommunications and Information Administration to look at ways that the spectrum could be shared with unlicensed users in the 5.9GHz band.

There’s also the problem with GPS technology itself. In urban environments, GPS fixes can be difficult at best, with buildings blocking parts of the constellation of satellites overhead at any time. That may not be a problem for some collision avoidance portions of the system—the vehicles in range of each other will have the same GPS data, and as a result, the same distortion of location to deal with. But “shadows” in GPS data could cause frequent errors in other systems dependent on the data, creating havoc in traffic flow systems as well as holes in safety coverage at intersections where the data might be different around the corner.