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Intervehicle Communications

June 13, 2012

Since I have some expertise in radio technology, It's not surprising that I worked on some radar projects during my time in industrial research. One of these was a weather radar system for aircraft; specifically, a search for new ways to avoid regions of the airspace that would lead to aircraft icing. Another was collision-avoidance radar for automobiles.

Radar on an automobile? Isn't that a little over the top? If you've ever driven in my neighborhood, you would realize why this might be useful. At the time I worked on the project, computing was not as developed as it is today. The radar part was easy. Since radar signals travel at the speed of light, the radar reflections from other automobiles were nearly instantaneous.

The problem was reflections from other objects that we needed to remove through computer processing. These signals are called "clutter," and in an airport radar system they're easy to remove, since they're static. In an automotive system, there's dynamic scatter, which was too hard to handle with the computer resources available at the time. Collision-avoidance radar for automobiles was an idea before its time.

There's no question that some sort of system of this type is needed. Five years ago, I wrote an article (Unsafe at Any Speed, February 6, 2007) that recalled the many famous physicists who were killed or injured in automobile accidents. Imagine the many not-so-famous lives impacted by the automobile. The National Highway Traffic Safety Administration reports that there were 5.4 million vehicle crashes in the US, with 2.2 million resulting injuries and 32,788 deaths, in 2010.[1]

Traffic Accident Memorial (Budapest)

Lower portion of a traffic accident victim's memorial in Óbuda, Hungary.

(Via Wikimedia Commons))

According to the Centers for Disease Control, motor vehicle crashes are the leading cause of death for ages 3 through 34.[2] Not only that, but the statistics for 2009 showed that more than 2.3 million drivers and passengers were treated in emergency departments as the result of motor vehicle accidents.[2] The economic impact of motor vehicle accidents, in terms of lifetime costs for individuals, was $70 billion in 2005.[2]

There are ways other than radar to attain situational awareness on the roadways. If you're just interested in the other vehicles in your area, you can borrow an approach used for decades by the military. IFF systems, for Identification Friend or Foe, are based on transponders. These are a combination of a transmitter and a receiver that operate by transmitting data upon receipt of a proper message.

There are benefits other than safety in such a transponder system that allows vehicles to keep track of each other. There might be ways to give drivers enough information to modify their route to prevent traffic delays. It's reported that US vehicle occupants waste about a full work week stuck in traffic each year. In the composite, that amounts to 4.8 billion wasted manhours and 3.9 billion gallons of wasted fuel.[1]

The US Department of Transportation is conducting research on an intelligent transportation system using inter-vehicle and roadside-to-vehicle communications.[3-4] The technology, which is much like a home's Wi-Fi wireless network connection, is called Dedicated Short Range Communications. There's a frequency allocation for such a system at 5.9 GHz, just above the 5.8 GHz ISM band used for many wireless devices.

Figure caption

Respect my space.

Artist's impression of Dedicated Short Range Communications.

(US Department of Transportation image))

Once the hardware is in place, likely by government mandate (just like seat belts), you can imagine the possibilities. One non-technical possibility would be reduced insurance rates, which is something the public would easily understand. The several hundred dollars added to the cost of an automobile could be recouped by a possible hundred dollars reduction in annual insurance rates.

The technical possibilities would include warning drivers of such dangers as icy roads, dangerous curves, and possible collisions. The automobile transponders could communicate with traffic signals and toll booths, and drivers could be warned of work zones and school zones.[4] One thing the government is doing right is designing the systems so that individual vehicles can't be tracked. Such a privacy feature is important to get public buy-in.

There were six "driver acceptance clinics" held from 2011-2012 to collect feedback from 688 drivers who participated in tests of a vehicle-to-vehicle communication system. Eighty-two percent of the drivers said that they liked the system, and ninety percent believed it would enhance safety.[3] Eight major motor vehicle manufacturers have partnered on this Connected Vehicle Safety Pilot Program, and the National Highway Traffic Safety Administration will consider further work and possible rulemaking by 2013. [3]


  1. Intelligent Transportation Systems Research Fact Sheets, US Department of Transportation.
  2. Injury Prevention & Control: Motor Vehicle Safety, Centers for Disease Control Web Site.
  3. New DOT Research Shows Drivers Support Connected Vehicle Technology, Appreciate Potential Safety Benefits, National Highway Traffic Safety Administration Press Release No. NHTSA 13-12, May 22, 2012.
  4. Safety Pilot Program Overview, Intelligent Transportation Systems, Department of Transportation, web site.

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