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Backstage of expressway - "traffic control systems" supporting the logistics

  • MitaCome to think of it, information about traffic jams on expressways can be acquired via the Internet or a cell phone. Does that information come from the traffic control system, too?
  • KawaguchiYes. Most of such traffic information comes from a traffic control system. The car navigation system (VICS), which drivers routinely use, also relies on the information provided from the traffic control system.
  • MitaSo, nearly all of the expressway traffic information that we see comes from the traffic control system.
  • KawaguchiThat's right. There is also another important role that the traffic control system plays. When a traffic accident occurs, it is used to notify the police, fire department, and other relevant organizations. For example, when someone reports a chain-reaction crash from an emergency telephone, it is the job of the traffic control system operators to notify the police, fire department, and about there being an accident and call an ambulance while providing drivers with related traffic information. In the event of an accident, the operators not only gather information but also notify relevant organizations.
  • MitaThat is very reassuring. But there are always cars on the road. And the condition of a traffic jam constantly changes. How do you keep track of the traffic conditions?
  • KawaguchiThe secret lies beneath the surface of the expressway.
  • MitaWhat? Beneath the surface of the expressway?
  • KogaMr. Nagano, a traffic control system expert, will explain it to you.
  • NaganoWe have sensors called traffic counters embedded beneath the surface of the expressway, and they react to every car passing over them. Using these traffic counters, we keep track of how much traffic is on the expressway and how fast the traffic is flowing. This vehicle passage information is collected in the traffic control system to create traffic jam information.
  • MitaThat means, whenever I drove on the expressway, my car got counted by those embedded sensors.
  • NaganoYes, absolutely. Though what I mentioned now is something that applies to expressways in general. On the Shin-Tomei Expressway that recently opened, we have cameras acting as traffic counters installed over the road, instead of beneath the road. The road-embedded counters are susceptible to damage by the weight of large trucks and other heavy vehicles. Also, since they are embedded beneath the road, they are difficult to maintain. NEXCO Central said that it decided to install cameras over the road for the Shin-Tomei Expressway in consideration of ease of maintenance and the capability to monitor traffic conditions on all lines in real time.
  • MitaI see.
  • NaganoThe Shin-Tomei Expressway is different in some other ways, too. For example, vehicle passage information is collected from traffic counters at intervals of five minutes on the existing expressways. But, on the Shin-Tomei Expressway, we collect the information at one-minute intervals. Traffic conditions change with every moment. So the new system is designed to provide more detailed traffic information.
  • MitaAt one-minute intervals! It's amazing that you provide traffic information that is so minute!
  • NaganoThe Shin-Tomei Expressway has all its facilities, from roadway sensors to the roadway control center, connected via an optical network. This has made it possible to collect detailed sensor information at a very high speed. The information displayed on the information terminals that you use to check traffic conditions in service areas on the Shin-Tomei Expressway is also updated every minute.

Picture:Information terminalInformation terminal

  • MitaWow, that's why the terminal information that I saw on the Shin-Tomei Expressway perfectly matched the actual traffic conditions!
  • KawaguchiThat's right. By the way, as Mr. Nagano has mentioned, roadway information is gathered at the roadway control center. The Shin-Tomei Expressway, in this respect, also has some features that are different from the other expressways.
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